fix(ci): forward-port to modern yar

- allow it to modify lock files while making test patches

we do not care about immutability / reproducible builds in the test patch
creation context

- use new "--dev" flag in place of old "--save-dev"

Author: mikehardy

.github/workflows/create_test_patches.yml

@@ -73,8 +73,9 @@ jobs:
           cd $HOME
           npx react-native init template --skip-install
           cd template
+          export YARN_ENABLE_IMMUTABLE_INSTALLS=false
           yarn
-          yarn add patch-package --save-dev
+          yarn add patch-package --dev
           mkdir patches || true
           for PACKAGE in $PACKAGE_LIST; do
             echo "Installing package $PACKAGE into fresh template app, then clobbering with PR version"