Enable pprof endpoints on metrics server

Using the helper from `pkg/runtime/pprof`, which follows the suggestion
from controller-runtime to use `AddMetricsExtraHandler`.

Signed-off-by: Hidde Beydals <[email protected]>

Author: hiddeco

go.mod

@@ -12,7 +12,7 @@ require (
 	github.com/fluxcd/pkg/gittestserver v0.1.0
 	github.com/fluxcd/pkg/helmtestserver v0.1.0
 	github.com/fluxcd/pkg/lockedfile v0.0.5
-	github.com/fluxcd/pkg/runtime v0.8.0
+	github.com/fluxcd/pkg/runtime v0.8.1
 	github.com/fluxcd/pkg/ssh v0.0.5
 	github.com/fluxcd/pkg/untar v0.0.5
 	github.com/fluxcd/pkg/version v0.0.1