chore(docs site): use git commit message for netlify build (#4900)

build/netlify-docs.js

@@ -1,16 +1,12 @@
 const sh = require('shelljs');
+const semver = require('semver');
 
-const GIT_CONTAINS = `git tag --contains ${process.env.COMMIT_REF}`;
-const output = sh.exec(GIT_CONTAINS, {async: false, silent:true}).stdout;
-
-console.log('CONTAINS command:', GIT_CONTAINS);
-console.log('BRANCH:', process.env.BRANCH);
-console.log('OUTPUT', output);
-
+const GIT_LOG = `git log --format=%B -n 1 ${process.env.COMMIT_REF}`;
+const output = sh.exec(GIT_LOG, {async: false, silent:true}).stdout;
 
 // if we're on master branch and not on a tagged commit,
 // error the build so it doesn't redeploy the docs
-if (process.env.BRANCH === 'master' && output === '') {
+if (process.env.BRANCH === 'master' && semver.valid(output.trim()) === null) {
   process.exit(1);
 
 // if we're on any other branch, we can regenerate docs