Add support for versionRegex

If set, used to extract version numbers from a release's tag via named groups. These versions will then
be used to determine whether prereleases predating the latest stable release are possibly
actually still to be included as they contain newer software versions (and are just earlier builds).

rpi-imager-json/.gitignore

@@ -1,2 +1,3 @@
 node_modules
 .vscode
+.env

rpi-imager-json/README.md

@@ -43,9 +43,15 @@ If set, the `init_format` to set on the entries. Otherwise whatever is in the sn
 
 If set and matches either a release's name or description, the release will be ignored.
 
+### `versionRegex`
+
+If set, used to extract version numbers from a release's tag via named groups. These versions will then
+be used to determine whether prereleases predating the latest stable release are possibly
+actually still to be included as they contain newer software versions (and are just earlier builds).
+
 ## Usage
 
-`.github/workflows/issue-cleanup.yml`:
+`.github/workflows/generate.yml`:
 
 ```yaml
 name: "Generate rpi-imager.json"
@@ -64,9 +70,12 @@ jobs:
         token: "${{ secrets.GITHUB_TOKEN }}"
         owner: OctoPrint
         repo: OctoPi-UpToDate
+        ignoreRegex: "mark:untested"
+        versionRegex: "^(?<octopi>.*?)-(?<octoprint>.*?)-\\d+$"
         output: ./files/rpi-imager.json
         nameStable: "OctoPi (stable)"
         namePrerelease: "OctoPi (prerelease)"
+        initFormat: systemd
     # ...
 ```
 
@@ -86,4 +95,4 @@ node src/index.js
 
 ```
 npm run build
-```
+```

rpi-imager-json/action.yml

@@ -21,6 +21,8 @@ inputs:
     description: "What init_format to set on the entries"
   ignoreRegex:
     description: "An ignore regex to scan for in the release name & description"
+  versionRegex:
+    description: "A regex to extract versions from the tag to compare when looking for newer prereleases published before latest stable"
 runs:
   using: "node12"
   main: "dist/index.js"