Make deepMatch report in linear time

The current implementation of the deepMatch() has the exponential runtime.
Given the long enough input and the pattern with multiple wildcards
it takes a while if ever to complete which can potentially be used
maliciously to cause a denial of service (cpu and memory consumption).

E.g. running this in the root of this repository
time yq eval '.jobs.publishDocker.steps.[] | select (.run == "****outputs")' .github/workflows/release.yml
gives on my laptop
25.11s user 0.06s system 99% cpu 25.182 total

Whereas the updated implementation gives
0.01s user 0.01s system 36% cpu 0.049 total

There are numerous similar CVEs reported for glob evaluation in
different shells/ftp-servers/libraries.

The replacement implementation with the linear runtime is shamelessly taken
verbatim from the briliant article by Russ Cox https://research.swtch.com/glob

pkg/yqlib/matchKeyString_test.go

@@ -0,0 +1,40 @@
+package yqlib
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestDeepMatch(t *testing.T) {
+	var tests = []struct {
+		name    string
+		pattern string
+		ok      bool
+	}{
+		{"", "", true},
+		{"", "x", false},
+		{"x", "", false},
+		{"abc", "abc", true},
+		{"abc", "*", true},
+		{"abc", "*c", true},
+		{"abc", "*b", false},
+		{"abc", "a*", true},
+		{"abc", "b*", false},
+		{"a", "a*", true},
+		{"a", "*a", true},
+		{"axbxcxdxe", "a*b*c*d*e*", true},
+		{"axbxcxdxexxx", "a*b*c*d*e*", true},
+		{"abxbbxdbxebxczzx", "a*b?c*x", true},
+		{"abxbbxdbxebxczzy", "a*b?c*x", false},
+		{strings.Repeat("a", 100), "a*a*a*a*b", false},
+		{"xxx", "*x", true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name+" "+tt.pattern, func(t *testing.T) {
+			if want, got := tt.ok, deepMatch(tt.name, tt.pattern); want != got {
+				t.Errorf("Expected %v got %v", want, got)
+			}
+		})
+	}
+}