lib/ignore: Replace lib/fnmatch with github.com/gobwas/glob

Because it's literally ten times faster:



	benchmark                  old ns/op     new ns/op     delta

	BenchmarkMatch-8           13842         1200          -91.33%

	BenchmarkMatchCached-8     139           147           +5.76%



	benchmark                  old allocs     new allocs     delta

	BenchmarkMatch-8           0              0              +0.00%

	BenchmarkMatchCached-8     0              0              +0.00%



	benchmark                  old bytes     new bytes     delta

	BenchmarkMatch-8           12            0             -100.00%

	BenchmarkMatchCached-8     0             0             +0.00%

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>")
+}