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/gopkg.in/yaml.v2/sorter.go

@@ -51,6 +51,15 @@ func (l keyList) Less(i, j int) bool {
 		}
 		var ai, bi int
 		var an, bn int64
+		if ar[i] == '0' || br[i] == '0' {
+			for j := i-1; j >= 0 && unicode.IsDigit(ar[j]); j-- {
+				if ar[j] != '0' {
+					an = 1
+					bn = 1
+					break
+				}
+			}
+		}
 		for ai = i; ai < len(ar) && unicode.IsDigit(ar[ai]); ai++ {
 			an = an*10 + int64(ar[ai]-'0')
 		}