[Tests] add NPM_CONFIG_LEGACY_PEER_DEPS to install steps

Author: ljharb

.github/workflows/node-4+.yml

@@ -62,8 +62,10 @@ jobs:
         name: 'nvm install ${{ matrix.node-version }} && npm install'
         with:
           node-version: ${{ matrix.node-version }}
-          after_install: NPM_CONFIG_LEGACY_PEER_DEPS=true npm install --no-save "eslint@${{ matrix.eslint }}"
+          after_install: npm install --no-save "eslint@${{ matrix.eslint }}"
           skip-ls-check: true
+        env:
+          NPM_CONFIG_LEGACY_PEER_DEPS: true
       - run: npm run unit-test
       - uses: codecov/codecov-action@v1
 

.github/workflows/node-pretest.yml

@@ -13,6 +13,8 @@ jobs:
         with:
           node-version: 'lts/*'
           skip-ls-check: true
+        env:
+          NPM_CONFIG_LEGACY_PEER_DEPS: true
       - run: npm run pretest
 
   posttest:
@@ -25,4 +27,7 @@ jobs:
         with:
           node-version: 'lts/*'
           skip-ls-check: true
+        env:
+          NPM_CONFIG_LEGACY_PEER_DEPS: true
+      - run: echo 'legacy-peer-deps=true' >> .npmrc
       - run: npm run posttest

.github/workflows/readme.yml

@@ -13,4 +13,6 @@ jobs:
         with:
           node-version: 'lts/*'
           skip-ls-check: true
+        env:
+          NPM_CONFIG_LEGACY_PEER_DEPS: true
       - run: npm run generate-list-of-rules