nix(loadtest): remove outdated PGRST_DB_URI default

This was required for v9 and earlier, but these don't build with the
current nix invocation anymore anyway. Even loadtesting against v10 does
not work, because `--version` is used in one of the wait scripts and
this was only added in v11.2.

So no need to pretend we'd support comparing against older versions.

nix/tools/loadtest.nix

@@ -53,13 +53,10 @@ let
         workingDir = "/";
       }
       ''
-        # previously required settings to make this work with older branches
         export PGRST_DB_ANON_ROLE="postgrest_test_anonymous"
-        export PGRST_DB_URI="postgresql://"
-        export PGRST_DB_SCHEMAS="test"
-
         export PGRST_DB_CONFIG="false"
         export PGRST_DB_POOL="1"
+        export PGRST_DB_SCHEMAS="test"
         export PGRST_DB_TX_END="rollback-allow-override"
         export PGRST_LOG_LEVEL="crit"
         export PGRST_JWT_SECRET="reallyreallyreallyreallyverysafe"

nix/tools/withTools.nix

@@ -236,18 +236,6 @@ let
         ${git}/bin/git worktree remove -f "$tmpdir" > /dev/null
       '';
 
-  legacyConfig =
-    writeText "legacy.conf"
-      ''
-        # Using this config file to support older postgrest versions for `postgrest-loadtest-against`
-        db-uri="$(PGRST_DB_URI)"
-        db-schema="$(PGRST_DB_SCHEMAS)"
-        db-anon-role="$(PGRST_DB_ANON_ROLE)"
-        db-pool="$(PGRST_DB_POOL)"
-        server-unix-socket="$(PGRST_SERVER_UNIX_SOCKET)"
-        log-level="$(PGRST_LOG_LEVEL)"
-      '';
-
   waitForPgrstReady =
     checkedShellScript
       {
@@ -334,11 +322,11 @@ let
           printf "done in %ss.\n" "$build_end"
         fi
 
-        ver=$($PGRST_CMD ${legacyConfig} --version)
+        ver=$($PGRST_CMD --version)
 
         echo -n "${commandName}: Starting $ver... "
 
-        $PGRST_CMD ${legacyConfig} > "$tmpdir"/run.log 2>&1 &
+        $PGRST_CMD > "$tmpdir"/run.log 2>&1 &
         pid=$!
         # shellcheck disable=SC2329
         cleanup() {