Update from upstream

[jnoconor]

Our current version of this buildpack does not support Heroku-20 (or even Heroku-18 it looks like). We can't switch to the stock buildpack because we rely on a connect_query option to do statement timeouts on queries through pgbouncer. There is an open PR for this in the main repo (heroku#95), but the outlook for getting it merged does not look good.

This PR merges the upstream changes and add our patch back on top.

Diff between heroku/heroku-buildpack-pgbouncer/main and vhx/heroku-buildpack-pgbouncer/update-from-upstream.

diff --git a/README.md b/README.md
index bbe74bc..4943043 100644
--- a/README.md
+++ b/README.md
@@ -139,6 +139,7 @@ Some settings are configurable through app config vars at runtime. Refer to the
 - `PGBOUNCER_SERVER_RESET_QUERY` Default is empty when pool mode is transaction, and "DISCARD ALL;" when session.
 - `PGBOUNCER_IGNORE_STARTUP_PARAMETERS` Adds parameters to ignore when pgbouncer is starting. Some postgres libraries, like Go's pq, append this parameter, making it impossible to use this buildpack. Default is empty and the most common ignored parameter is `extra_float_digits`. Multiple parameters can be seperated via commas. Example: `PGBOUNCER_IGNORE_STARTUP_PARAMETERS="extra_float_digits, some_other_param"`
 - `PGBOUNCER_QUERY_WAIT_TIMEOUT` Default is 120 seconds, helps when the server is down or the database rejects connections for any reason. If this is disabled, clients will be queued infinitely.
+- `PGBOUNCER_CONNECT_QUERY` Query to be executed after a connection is established, but before allowing the connection to be used by any clients. If the query raises errors, they are logged but ignored otherwise.

 For more info, see [CONTRIBUTING.md](CONTRIBUTING.md)

diff --git a/bin/gen-pgbouncer-conf.sh b/bin/gen-pgbouncer-conf.sh
index 7a45a39..1308047 100644
--- a/bin/gen-pgbouncer-conf.sh
+++ b/bin/gen-pgbouncer-conf.sh
@@ -66,8 +66,13 @@ do
 "$DB_USER" "$DB_MD5_PASS"
 EOFEOF

+  CONNECT_QUERY_PARAM=''
+  if [[ "$PGBOUNCER_CONNECT_QUERY" ]]; then
+    CONNECT_QUERY_PARAM="connect_query='${PGBOUNCER_CONNECT_QUERY//\'/\'\'}'"
+  fi
+
   cat >> /app/vendor/pgbouncer/pgbouncer.ini << EOFEOF
-$CLIENT_DB_NAME= host=$DB_HOST dbname=$DB_NAME port=$DB_PORT
+$CLIENT_DB_NAME= host=$DB_HOST dbname=$DB_NAME port=$DB_PORT $CONNECT_QUERY_PARAM
 EOFEOF

   let "n += 1"

[elliterate]

Looks like this includes an upgrade for pgbouncer itself from 1.7.2 to 1.14.0. Probably worth crafting a test plan and watching the rollout carefully.