chore: add constraints file check for python samples (#170)

This is the sibling PR to https://github.com/GoogleCloudPlatform/python-docs-samples/pull/5611
and this is the issue opened for it https://github.com/GoogleCloudPlatform/python-docs-samples/issues/5549
diff --git a/synth.metadata b/synth.metadata
index c66286d..24df57c 100644
--- a/synth.metadata
+++ b/synth.metadata
@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/python-api-core.git",
-        "sha": "49c6755a21215bbb457b60db91bab098185b77da"
+        "sha": "8c7ac29ce8b1680fc0991f5001ed4a6ad580f951"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "5b5bf6d519b2d658d9f2e483d9f6f3d0ba8ee6bc"
+        "sha": "0a071b3460344886297a304253bf924aa68ddb7e"
       }
     }
   ],