chore: add .envrc and .direnv to .gitignore (#1680)

This PR adds some common files and folders used when creating local
development environments. Useful for testing the package with different
Node.js versions without relying on nvm or similar packages.

Author: simeonoff

.gitignore

@@ -30,3 +30,7 @@ custom-elements.json
 
 # Localization data
 i18nRepo
+
+# Development environment
+.envrc
+.direnv