Update minecraft-server to the java17 line (0.4.0+upjava17)

Second of the three Java-line publishes. Only the two version lines in
Chart.yaml change; the rendered output differs from the published java8 chart
in exactly one line, the image tag.

The CI install values move along with the appVersion: the image tag is the
Java line, so the JVM is fixed per published chart version and the Minecraft
version has to match it (Java 8 runs up to 1.16.5, 1.18-1.20.4 need Java 17).
No single Minecraft version boots on all three lines, and because the chart
has no probes a version the JVM cannot load would still leave a green
install-test behind. minecraft.version therefore moves 1.12.2 -> 1.20.1.
ci/ is outside the chart directory and is neither packaged nor published.

minecraft-server/Chart.yaml

@@ -15,10 +15,10 @@ type: application
 # This is the chart version. This version number should be incremented each time you make changes
 # to the chart and its templates, including the app version.
 # Versions are expected to follow Semantic Versioning (https://semver.org/)
-version: 0.4.0+upjava8
+version: 0.4.0+upjava17
 
 # This is the version number of the application being deployed. This version number should be
 # incremented each time you make changes to the application. Versions are not expected to
 # follow Semantic Versioning. They should reflect the version the application is using.
 # It is recommended to use it with quotes.
-appVersion: "java8"
+appVersion: "java17"