Give compliance a pkgPath

Change the pkgPath of compliance to android/soong/tools/compliance
to distinguish it from the standard library.

Also add a go.mod file so that the Go tools can find the package.

Test: go test ./...
Change-Id: I061be2b91378db6508e9c88be2548648af8be4e7
diff --git a/tools/compliance/cmd/dumpresolutions_test.go b/tools/compliance/cmd/dumpresolutions_test.go
index 1abfac7..50a6319 100644
--- a/tools/compliance/cmd/dumpresolutions_test.go
+++ b/tools/compliance/cmd/dumpresolutions_test.go
@@ -16,10 +16,11 @@
 
 import (
 	"bytes"
-	"compliance"
 	"fmt"
 	"strings"
 	"testing"
+
+	"android/soong/tools/compliance"
 )
 
 func Test_plaintext(t *testing.T) {