Update release instructions for new Github branch protection rules. (#1430)
Update release instructions for new Github branch protection rules. (#1430)

Now protected branches can be specified with a pattern, so we can protect all
release branches with one rule. See
https://help.github.com/articles/about-protected-branches/.  There is no need to
enable branch protection when making a release.
census-instrumentation/opencensus-java,bogdandrutu/instrumentation-java,songy23/instrumentation-java,sebright/opencensus-java,bogdandrutu/opencensus-java,sebright/opencensus-java,songy23/instrumentation-java,bogdandrutu/instrumentation-java,sebright/opencensus-java,bogdandrutu/opencensus-java,sebright/instrumentation-java,census-instrumentation/opencensus-java,census-instrumentation/opencensus-java,sebright/instrumentation-java,songy23/instrumentation-java,bogdandrutu/opencensus-java