chore: add script to upgrade all packages and run it (#1673)

scripts/upgrade_all.sh

@@ -0,0 +1,14 @@
+#!/bin/sh -e
+
+# A script for upgrading dependencies for all packages in the monorepo.
+# Using a hard-coded list of packages for now, but could be improved to
+# automatically find all packages in the monorepo.
+PACKAGES='artifact_proxy discord_gcp_alerts jwt redis_client scoped shorebird_cli shorebird_code_push_client shorebird_code_push_protocol'
+
+for PACKAGE_DIR in $PACKAGES
+do
+    echo $PACKAGE_DIR
+    cd packages/$PACKAGE_DIR
+    dart pub upgrade
+    cd ../..
+done