Fixes for publish workflows (#1319)

Summary:
Pull Request resolved: https://github.com/facebook/yoga/pull/1319

This fixes a few issues encountered during publishing Yoga `2.0.0-beta.1`.

1. The tag trigger was missing quotes needed to be valid syntax
2. `pod trunk publish` must be run with `--synchronous` if we are publishing a package that relies on another just published package. There does not seem to be a way to just publish evertything at once.
3. `yarn publish` was not reading the NPM auth token from the environment, so we write it to a `.npmrc` before publishing.
4. The root `.gitignore` was not updated when moving to yarn workspaces to ignore `node_modules`, so the OSS Yoga repo (not internal) will, try to add its contents after `yarn install`.

Reviewed By: cortinico

Differential Revision: D47135994

fbshipit-source-id: d8c9b05176a98443be1ebc7cf74996f22520d20d

.gitignore

@@ -6,6 +6,7 @@
 /.buckd
 /gentest/test.html
 .buck-java11
+node_modules
 
 # Jekyll
 /.sass-cache/