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/btree_test.go

@@ -0,0 +1,90 @@
+package match
+
+import (
+	"testing"
+)
+
+func TestBTree(t *testing.T) {
+	for id, test := range []struct {
+		tree BTree
+		str  string
+		exp  bool
+	}{
+		{
+			NewBTree(NewText("abc"), NewSuper(), NewSuper()),
+			"abc",
+			true,
+		},
+		{
+			NewBTree(NewText("a"), NewSingle(nil), NewSingle(nil)),
+			"aaa",
+			true,
+		},
+		{
+			NewBTree(NewText("b"), NewSingle(nil), nil),
+			"bbb",
+			false,
+		},
+		{
+			NewBTree(
+				NewText("c"),
+				NewBTree(
+					NewSingle(nil),
+					NewSuper(),
+					nil,
+				),
+				nil,
+			),
+			"abc",
+			true,
+		},
+	} {
+		act := test.tree.Match(test.str)
+		if act != test.exp {
+			t.Errorf("#%d match %q error: act: %t; exp: %t", id, test.str, act, test.exp)
+			continue
+		}
+	}
+}
+
+type fakeMatcher struct {
+	len  int
+	name string
+}
+
+func (f *fakeMatcher) Match(string) bool {
+	return true
+}
+
+var i = 3
+
+func (f *fakeMatcher) Index(s string) (int, []int) {
+	seg := make([]int, 0, i)
+	for x := 0; x < i; x++ {
+		seg = append(seg, x)
+	}
+	return 0, seg
+}
+func (f *fakeMatcher) Len() int {
+	return f.len
+}
+func (f *fakeMatcher) String() string {
+	return f.name
+}
+
+func BenchmarkMatchBTree(b *testing.B) {
+	l := &fakeMatcher{4, "left_fake"}
+	r := &fakeMatcher{4, "right_fake"}
+	v := &fakeMatcher{2, "value_fake"}
+
+	// must be <= len(l + r + v)
+	fixture := "abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij"
+
+	bt := NewBTree(v, l, r)
+
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			bt.Match(fixture)
+		}
+	})
+}