chore: Track flagsmith-php-sdk 5.1.0 (#6589)

Co-authored-by: flagsmith-engineering[bot] <flagsmith-engineering[bot]@users.noreply.github.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: 3 people

api/app_analytics/constants.py

@@ -55,6 +55,7 @@
     "flagsmith-php-sdk": [
         "unknown",
         "5.0.0",
+        "5.1.0",
     ],
     "flagsmith-python-sdk": [
         "unknown",