Update versions-manifest (actions#206)

Author: github-actions[bot]

versions-manifest.json

@@ -2635,6 +2635,40 @@
       }
     ]
   },
+  {
+    "version": "3.8.15",
+    "stable": true,
+    "release_url": "https://github.com/actions/python-versions/releases/tag/3.8.15-3582057865",
+    "files": [
+      {
+        "filename": "python-3.8.15-darwin-x64.tar.gz",
+        "arch": "x64",
+        "platform": "darwin",
+        "download_url": "https://github.com/actions/python-versions/releases/download/3.8.15-3582057865/python-3.8.15-darwin-x64.tar.gz"
+      },
+      {
+        "filename": "python-3.8.15-linux-18.04-x64.tar.gz",
+        "arch": "x64",
+        "platform": "linux",
+        "platform_version": "18.04",
+        "download_url": "https://github.com/actions/python-versions/releases/download/3.8.15-3582057865/python-3.8.15-linux-18.04-x64.tar.gz"
+      },
+      {
+        "filename": "python-3.8.15-linux-20.04-x64.tar.gz",
+        "arch": "x64",
+        "platform": "linux",
+        "platform_version": "20.04",
+        "download_url": "https://github.com/actions/python-versions/releases/download/3.8.15-3582057865/python-3.8.15-linux-20.04-x64.tar.gz"
+      },
+      {
+        "filename": "python-3.8.15-linux-22.04-x64.tar.gz",
+        "arch": "x64",
+        "platform": "linux",
+        "platform_version": "22.04",
+        "download_url": "https://github.com/actions/python-versions/releases/download/3.8.15-3582057865/python-3.8.15-linux-22.04-x64.tar.gz"
+      }
+    ]
+  },
   {
     "version": "3.8.14",
     "stable": true,