Implement webhook branch filter (#7791)

* Fix validate() function to handle errors in embedded anon structs

* Implement webhook branch filter

See #2025, #3998.

vendor/github.com/gobwas/glob/match/nothing.go

@@ -0,0 +1,27 @@
+package match
+
+import (
+	"fmt"
+)
+
+type Nothing struct{}
+
+func NewNothing() Nothing {
+	return Nothing{}
+}
+
+func (self Nothing) Match(s string) bool {
+	return len(s) == 0
+}
+
+func (self Nothing) Index(s string) (int, []int) {
+	return 0, segments0
+}
+
+func (self Nothing) Len() int {
+	return lenZero
+}
+
+func (self Nothing) String() string {
+	return fmt.Sprintf("<nothing>")
+}