chore: Update CI action to node 18.x (cloudevents#533)

* Update CI action to node 18.x

Signed-off-by: Jordan Moore <1930631+OneCricketeer@users.noreply.github.com>

* doc: update README

Signed-off-by: Jordan Moore <1930631+OneCricketeer@users.noreply.github.com>

---------

Signed-off-by: Jordan Moore <1930631+OneCricketeer@users.noreply.github.com>

Author: OneCricketeer

.github/workflows/nodejs-ci-action.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node-version: [12.x, 14.x, 16.x]
+        node-version: [12.x, 14.x, 16.x, 18.x]
 
     steps:
     - uses: actions/checkout@v2
@@ -37,7 +37,7 @@ jobs:
     - name: Generate coverage report
       uses: actions/setup-node@v1
       with:
-        node-version: 16.x
+        node-version: 18.x
     - run: npm ci
     - run: npm run build --if-present
     - run: npm run coverage
@@ -60,7 +60,7 @@ jobs:
     - name: Upload coverage report to codacy
       uses: actions/setup-node@v1
       with:
-        node-version: 16.x
+        node-version: 18.x
     - run: |
         ( [[ "${CODACY_PROJECT_TOKEN}" != ""  ]] && npm run coverage-publish ) || echo "Coverage report not published"
       env:

README.md

@@ -19,7 +19,7 @@ _Note:_ Supports CloudEvent version 1.0
 ## Installation
 
 The CloudEvents SDK requires a current LTS version of Node.js. At the moment
-those are Node.js 12.x, Node.js 14.x and Node.js 16.x. To install in your Node.js project:
+those are Node.js 12.x, Node.js 14.x, Node.js 16.x, and Node.js 18.x. To install in your Node.js project:
 
 ```console
 npm install cloudevents