Release management using CircleCI (#3498)

* Release management using CircleCI

* Changelog updated

scripts/release_management/github-public-newbranch.bash

@@ -0,0 +1,28 @@
+#!/bin/sh
+
+# github-public-newbranch.bash - create public branch from the security repository
+
+set -euo pipefail
+
+# Create new branch
+BRANCH="${CIRCLE_TAG:-v0.0.0}-security-`date -u +%Y%m%d%H%M%S`"
+# Check if the patch release exist already as a branch
+if [ -n "`git branch | grep '${BRANCH}'`" ]; then
+  echo "WARNING: Branch ${BRANCH} already exists."
+else
+  echo "Creating branch ${BRANCH}."
+  git branch "${BRANCH}"
+fi
+
+# ... and check it out
+git checkout "${BRANCH}"
+
+# Add entry to public repository
+git remote add tendermint-origin git@github.com:tendermint/tendermint.git
+
+# Push branch and tag to public repository
+git push tendermint-origin
+git push tendermint-origin --tags
+
+# Create a PR from the public branch to the assumed release branch in public (release branch has to exist)
+python -u scripts/release_management/github-openpr.py --head "${BRANCH}" --base "${BRANCH:%.*}"