add synapse update script (without worker support)

even tho it's not complicated and there are multiple correct ways, i think it's better if we have one common update strategy to avoid conflicts or other errors in the future. this shall be expanded for worker support in the future.

updates/synapse.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+set -e
+
+activate="$HOME/synapse/env/bin/activate"
+
+if [ ! -f $activate ];
+then
+        echo ">>> FATAL: Synapse env not detected. Stopping. Please adjust the script."
+        exit 1
+fi
+
+source $activate
+
+pip install --upgrade 'matrix-synapse[postgres]' pip
+
+systemctl --user restart synapse
+
+sleep 2
+echo
+echo ">>> Synapse has been restarted and"
+echo ">>> is now reporting this version:"
+curl -s localhost:8008/_synapse/admin/v1/server_version|jq
+echo
+
+systemctl --user status synapse