build(node): don't throw on deprecation in unit tests (#76)

Fixes #1134 🦕 Removes the commit body and relative PR# from the commit message. For example, for this commit: googleapis/synthtool@9763f20 `post-processor-changes.txt` would contain ``` build: enable npm for php/python builds Source-Link: googleapis/synthtool@9763f20 ``` instead of ``` build: enable npm for php/python builds (#1133) * build: enable npm for php/python builds * update comment Source-Link: googleapis/synthtool@9763f20 ``` Source-Link: googleapis/synthtool@e934b93 Post-Processor: gcr.io/repo-automation-bots/owlbot-nodejs:latest@sha256:805e2e389eafefa5ed484c30b83a7a875e6b1c7ee125d812e8b01ecc531c3fac

Author: gcf-owl-bot[bot]

.github/.OwlBot.lock.yaml

@@ -1,3 +1,3 @@
 docker:
  image: gcr.io/repo-automation-bots/owlbot-nodejs:latest
- digest: sha256:c9c7828c165b1985579098978877935ee52dda2b1b538087514fd24fa2443e7a
+ digest: sha256:805e2e389eafefa5ed484c30b83a7a875e6b1c7ee125d812e8b01ecc531c3fac

.github/workflows/ci.yaml

@@ -24,6 +24,8 @@ jobs:
  - run: rm -rf node_modules
  - run: npm install
  - run: npm test
+ env:
+ MOCHA_THROW_DEPRECATION: false
  windows:
  runs-on: windows-latest
  steps:
@@ -33,6 +35,8 @@ jobs:
  node-version: 14
  - run: npm install
  - run: npm test
+ env:
+ MOCHA_THROW_DEPRECATION: false
  lint:
  runs-on: ubuntu-latest
  steps: