[chore] Update Go version to 1.18 (#444)

* linting with new golangci-lint version

* update go to 1.18

* bump versions in drone.yml

* use new runtime/debug package for version info

* remove Commit build flag from goreleaser

* remove mock commit + version from build script

* go fmt

* add dummy version env flag to test container

* install git in golang container for testing

* only set versionString if Version is defined

internal/validate/structvalidation.go

@@ -59,5 +59,10 @@ func processValidationError(err error) error {
 		panic(ive)
 	}
 
-	return err.(validator.ValidationErrors)
+	valErr, ok := err.(validator.ValidationErrors)
+	if !ok {
+		panic("*validator.InvalidValidationError could not be coerced to validator.ValidationErrors")
+	}
+
+	return valErr
 }