Upgrade to go-execute/v2

Upgrades to go-execute/v2 and updates various other
dependencies.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

vendor/github.com/go-logr/logr/discard.go

@@ -20,35 +20,5 @@ package logr
 // used whenever the caller is not interested in the logs.  Logger instances
 // produced by this function always compare as equal.
 func Discard() Logger {
-	return Logger{
-		level: 0,
-		sink:  discardLogSink{},
-	}
-}
-
-// discardLogSink is a LogSink that discards all messages.
-type discardLogSink struct{}
-
-// Verify that it actually implements the interface
-var _ LogSink = discardLogSink{}
-
-func (l discardLogSink) Init(RuntimeInfo) {
-}
-
-func (l discardLogSink) Enabled(int) bool {
-	return false
-}
-
-func (l discardLogSink) Info(int, string, ...interface{}) {
-}
-
-func (l discardLogSink) Error(error, string, ...interface{}) {
-}
-
-func (l discardLogSink) WithValues(...interface{}) LogSink {
-	return l
-}
-
-func (l discardLogSink) WithName(string) LogSink {
-	return l
+	return New(nil)
 }