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/glob.go

@@ -0,0 +1,75 @@
+package glob
+
+// Glob represents compiled glob pattern.
+type Glob interface {
+	Match(string) bool
+}
+
+// Compile creates Glob for given pattern and strings (if any present after pattern) as separators.
+// The pattern syntax is:
+//
+//    pattern:
+//        { term }
+//
+//    term:
+//        `*`         matches any sequence of non-separator characters
+//        `**`        matches any sequence of characters
+//        `?`         matches any single non-separator character
+//        `[` [ `!` ] { character-range } `]`
+//                    character class (must be non-empty)
+//        `{` pattern-list `}`
+//                    pattern alternatives
+//        c           matches character c (c != `*`, `**`, `?`, `\`, `[`, `{`, `}`)
+//        `\` c       matches character c
+//
+//    character-range:
+//        c           matches character c (c != `\\`, `-`, `]`)
+//        `\` c       matches character c
+//        lo `-` hi   matches character c for lo <= c <= hi
+//
+//    pattern-list:
+//        pattern { `,` pattern }
+//                    comma-separated (without spaces) patterns
+//
+func Compile(pattern string, separators ...rune) (Glob, error) {
+	ast, err := parse(newLexer(pattern))
+	if err != nil {
+		return nil, err
+	}
+
+	matcher, err := compile(ast, separators)
+	if err != nil {
+		return nil, err
+	}
+
+	return matcher, nil
+}
+
+// MustCompile is the same as Compile, except that if Compile returns error, this will panic
+func MustCompile(pattern string, separators ...rune) Glob {
+	g, err := Compile(pattern, separators...)
+	if err != nil {
+		panic(err)
+	}
+
+	return g
+}
+
+// QuoteMeta returns a string that quotes all glob pattern meta characters
+// inside the argument text; For example, QuoteMeta(`{foo*}`) returns `\[foo\*\]`.
+func QuoteMeta(s string) string {
+	b := make([]byte, 2*len(s))
+
+	// a byte loop is correct because all meta characters are ASCII
+	j := 0
+	for i := 0; i < len(s); i++ {
+		if special(s[i]) {
+			b[j] = '\\'
+			j++
+		}
+		b[j] = s[i]
+		j++
+	}
+
+	return string(b[0:j])
+}