screen-lock: recognise the colour build by its version scheme; its version line never says color

modules/screen-lock/cmd/screen-lock-tools/manifest_test.go

@@ -38,7 +38,7 @@ func TestTheColourBuildIsKeptWithAFallbackAndXscreensaverGoes(t *testing.T) {
 	c := wrapper["content"].(string)
 	// The colour build's options only once it has said it is the colour build: the distribution's
 	// i3lock refuses an option it does not know, and the screen would not lock at all.
-	check := strings.Index(c, "i3lock --version 2>&1 | grep -qi color")
+	check := strings.Index(c, `i3lock --version 2>&1 | grep -qE '[0-9]\.c\.[0-9]'`)
 	fallback := strings.Index(c, "\nelse\n")
 	for _, colourOnly := range []string{"--ring-color", "--blur", "--clock", "--indicator", "--time-str"} {
 		at := strings.Index(c, colourOnly)