ci: removing Alpine Renovate version updating

Removing the custom manager for updating all the repology lines with the Alpine
image's version, as we changed to using the Rust Alpine image.

renovate.json

@@ -20,20 +20,6 @@
         "# renovate: datasource=(?<datasource>.*?) depName=(?<depName>.*?)( versioning=(?<versioning>.*?))?\\s.+_VERSION=\"(?<currentValue>.*?)\"\\s"
       ]
     },
-    {
-      "customType": "regex",
-      "fileMatch": [
-        "^Earthfile$"
-      ],
-      "matchStrings": [
-        "# renovate: datasource=repology packageName=alpine_(?<currentValue>\\d+[._]\\d+)"
-      ],
-      "currentValueTemplate": "{{{ replace '_' '.' currentValue }}}",
-      "datasourceTemplate": "docker",
-      "depNameTemplate": "alpine",
-      "versioningTemplate": "regex:^(?<major>\\d+)[._](?<minor>\\d+)$",
-      "autoReplaceStringTemplate": "# renovate: datasource=repology packageName=alpine_{{{newMajor}}}_{{{newMinor}}}"
-    },
     {
       "customType": "regex",
       "fileMatch": [