Update docs for v5

Signed-off-by: Dmitriy Zaporozhets <[email protected]>

Author: dzaporozhets

doc/update-from-v4-to-v5.md

@@ -0,0 +1,16 @@
+# Update Runner from v4 to v5
+
+## 1. Stop runner
+
+    sudo service gitlab-ci-runner stop
+
+## 2. Get recent code
+
+    sudo su gitlab_ci_runner
+    cd ~/gitlab-ci-runner
+    git fetch origin
+    git checkout 5-0-stable
+
+## 3. Start Runner
+
+    sudo service gitlab-ci-runner start