Use Delve v0.12.1 instead of master

vendor/github.com/derekparker/delve/version/version.go

@@ -0,0 +1,25 @@
+package version
+
+import "fmt"
+
+// Version represents the current version of Delve.
+type Version struct {
+	Major    string
+	Minor    string
+	Patch    string
+	Metadata string
+	Build    string
+}
+
+var (
+	// DelveVersion is the current version of Delve.
+	DelveVersion = Version{Major: "0", Minor: "12", Patch: "1", Metadata: ""}
+)
+
+func (v Version) String() string {
+	ver := fmt.Sprintf("Version: %s.%s.%s", v.Major, v.Minor, v.Patch)
+	if v.Metadata != "" {
+		ver += "-" + v.Metadata
+	}
+	return fmt.Sprintf("%s\nBuild: %s", ver, v.Build)
+}