Add information about yarn lint & test into CONTRIBUTING.md; Add better description of `yarn build` step in the pipeline

.github/workflows/main.yml

@@ -19,7 +19,7 @@ jobs:
       - run: yarn lint
       - run: yarn test
       - run: yarn build || { echo "build command should always succeed" ; exit 61; }
-      - run: yarn build --quiet && git diff --quiet action || { echo "action should be auto generated" ; exit 62; }
+      - run: yarn build --quiet && git diff --quiet action || { echo "ERROR - index.js is different from repository version. Forgot to run `yarn build`?" ; exit 62; }
 
   testAllModesLikeInTheReadme:
     name: Test in ${{ matrix.testMode }} on version ${{ matrix.unityVersion }}

CONTRIBUTING.md

@@ -31,8 +31,8 @@ You have [Node](https://nodejs.org/) installed at v12.2.0+ and [Yarn](https://ya
 Please note that commit hooks will run automatically to perform some tasks;
 
 - format your code
-- run tests
-- build distributable files
+- run tests & lint - `yarn lint && yarn test`
+- build distributable files - `yarn build`
 
 #### License