[DPE-6651] Update snap revisions to new builds with updated percona packages (#224)

## Issue
We have new snap builds that include new versions of percona packages

## Solution
Update snap revisions

Author: shayancanonical

src/snap.py

@@ -25,8 +25,8 @@
 _SNAP_NAME = "charmed-mysql"
 REVISIONS: typing.Dict[str, str] = {
     # Keep in sync with `workload_version` file
-    "x86_64": "134",
-    "aarch64": "135",
+    "x86_64": "139",
+    "aarch64": "138",
 }
 revision = REVISIONS[platform.machine()]
 _snap = snap_lib.SnapCache()[_SNAP_NAME]