[Security] Inject content script only on github and gitlab (#227)

* Inject content script only on github and gitlab

* fix indents in extension manifest

Author: lucacasonato

extension/manifest.json

@@ -15,7 +15,8 @@
 	"content_scripts": [
 		{
 			"matches": [
-				"https://*/*"
+				"https://github.com/*",
+				"https://gitlab.com/*"
 			],
 			"js": [
 				"out/content.js"
@@ -29,4 +30,4 @@
 		"default_title": "Sail",
 		"default_popup": "out/popup.html"
 	}
-}
+}