vendor: update all dependencies

* Update all dependencies
  * Remove all `[[constraint]]` from Gopkg.toml
  * Add in the minimum number of `[[override]]` to build
  * Remove go get of github.com/inconshreveable/mousetrap as it is vendored
  * Update docs with new policy on constraints

vendor/cloud.google.com/go/firestore/testdata/VERSION

@@ -1 +1 @@
-SHA1(/usr/local/google/home/jba/go/src/github.com/GoogleCloudPlatform/google-cloud-common/testing/firestore/testdata/test-suite.binproto)= 3047565564b81726a57d7db719704ea8bf17a9ab
+SHA1(/usr/local/google/home/jba/go/src/github.com/GoogleCloudPlatform/google-cloud-common/testing/firestore/testdata/test-suite.binproto)= 1502b0250a2ecd854b80509e3e456e46ade89ea7

vendor/cloud.google.com/go/firestore/testdata/query-bad-NaN.textproto

@@ -0,0 +1,19 @@
+# DO NOT MODIFY. This file was generated by
+# github.com/GoogleCloudPlatform/google-cloud-common/testing/firestore/cmd/generate-firestore-tests/generate-firestore-tests.go.
+
+# You can only compare NaN for equality.
+
+description: "query: where clause with non-== comparison with NaN"
+query: <
+  coll_path: "projects/projectID/databases/(default)/documents/C"
+  clauses: <
+    where: <
+      path: <
+        field: "a"
+      >
+      op: "<"
+      json_value: "\"NaN\""
+    >
+  >
+  is_error: true
+>

vendor/cloud.google.com/go/firestore/testdata/query-bad-null.textproto

@@ -0,0 +1,19 @@
+# DO NOT MODIFY. This file was generated by
+# github.com/GoogleCloudPlatform/google-cloud-common/testing/firestore/cmd/generate-firestore-tests/generate-firestore-tests.go.
+
+# You can only compare Null for equality.
+
+description: "query: where clause with non-== comparison with Null"
+query: <
+  coll_path: "projects/projectID/databases/(default)/documents/C"
+  clauses: <
+    where: <
+      path: <
+        field: "a"
+      >
+      op: ">"
+      json_value: "null"
+    >
+  >
+  is_error: true
+>

vendor/cloud.google.com/go/firestore/testdata/query-where-NaN.textproto

@@ -0,0 +1,31 @@
+# DO NOT MODIFY. This file was generated by
+# github.com/GoogleCloudPlatform/google-cloud-common/testing/firestore/cmd/generate-firestore-tests/generate-firestore-tests.go.
+
+# A Where clause that tests for equality with NaN results in a unary filter.
+
+description: "query: a Where clause comparing to NaN"
+query: <
+  coll_path: "projects/projectID/databases/(default)/documents/C"
+  clauses: <
+    where: <
+      path: <
+        field: "a"
+      >
+      op: "=="
+      json_value: "\"NaN\""
+    >
+  >
+  query: <
+    from: <
+      collection_id: "C"
+    >
+    where: <
+      unary_filter: <
+        op: IS_NAN
+        field: <
+          field_path: "a"
+        >
+      >
+    >
+  >
+>

vendor/cloud.google.com/go/firestore/testdata/query-where-null.textproto

@@ -0,0 +1,31 @@
+# DO NOT MODIFY. This file was generated by
+# github.com/GoogleCloudPlatform/google-cloud-common/testing/firestore/cmd/generate-firestore-tests/generate-firestore-tests.go.
+
+# A Where clause that tests for equality with null results in a unary filter.
+
+description: "query: a Where clause comparing to null"
+query: <
+  coll_path: "projects/projectID/databases/(default)/documents/C"
+  clauses: <
+    where: <
+      path: <
+        field: "a"
+      >
+      op: "=="
+      json_value: "null"
+    >
+  >
+  query: <
+    from: <
+      collection_id: "C"
+    >
+    where: <
+      unary_filter: <
+        op: IS_NULL
+        field: <
+          field_path: "a"
+        >
+      >
+    >
+  >
+>

vendor/cloud.google.com/go/firestore/testdata/update-paths-fp-del.textproto

@@ -0,0 +1,47 @@
+# DO NOT MODIFY. This file was generated by
+# github.com/GoogleCloudPlatform/google-cloud-common/testing/firestore/cmd/generate-firestore-tests/generate-firestore-tests.go.
+
+# If one nested field is deleted, and another isn't, preserve the second.
+
+description: "update-paths: field paths with delete"
+update_paths: <
+  doc_ref_path: "projects/projectID/databases/(default)/documents/C/d"
+  field_paths: <
+    field: "foo"
+    field: "bar"
+  >
+  field_paths: <
+    field: "foo"
+    field: "delete"
+  >
+  json_values: "1"
+  json_values: "\"Delete\""
+  request: <
+    database: "projects/projectID/databases/(default)"
+    writes: <
+      update: <
+        name: "projects/projectID/databases/(default)/documents/C/d"
+        fields: <
+          key: "foo"
+          value: <
+            map_value: <
+              fields: <
+                key: "bar"
+                value: <
+                  integer_value: 1
+                >
+              >
+            >
+          >
+        >
+      >
+      update_mask: <
+        field_paths: "foo.bar"
+        field_paths: "foo.delete"
+      >
+      current_document: <
+        exists: true
+      >
+    >
+  >
+>