[Bug] JCenter not available anymore, replace with MavenCentral

[cremfert]

Describe the bug Since JCenter is going down, the build.gradle file should be updated to use mavenCentral() instead of jcenter(). However, if changed manually, zxing could not be found also, as the used version is not in Maven anymore: https://repo.maven.apache.org/maven2/me/dm7/barcodescanner/zxing/1.9.13/zxing-1.9.13.pom

To Reproduce Steps to reproduce the behavior:

1. Include barcode_scan2 latest version in pubspec.yml
2. Run flutter build apk
3. If not already downloaded, a validity check error for jcenter.bintray.com comes up.

Expected behavior The app should build.

Screenshots

Logs

> Could not resolve org.glassfish.jaxb:jaxb-runtime:2.2.11.
     Required by:
         project :barcode_scan2 > com.android.tools.build:gradle:3.5.3 > com.android.tools.build:builder:3.5.3 > com.android.tools:sdklib:26.5.3 > com.android.tools:repository:26.5.3
      > Could not resolve org.glassfish.jaxb:jaxb-runtime:2.2.11.
         > Could not get resource 'https://jcenter.bintray.com/org/glassfish/jaxb/jaxb-runtime/2.2.11/jaxb-runtime-2.2.11.pom'.
            > Could not GET 'https://jcenter.bintray.com/org/glassfish/jaxb/jaxb-runtime/2.2.11/jaxb-runtime-2.2.11.pom'.
               > PKIX path validation failed: java.security.cert.CertPathValidatorException: validity check failed

Environment (please complete the following information):

• [ ] iOS? Version: ...
• [x] Android? Version: 30
• [ ] Real Device? Which?: ...
• [ ] Emulator/Simulator? Which?: ...
• Version of barcode_scan
• Output of flutter --version:

  Flutter v 2.5.3

Additional context

[mono0926]

Please write the appropriate title instead of [Bug].

[cremfert]

Sorry, missed it. I corrected it.

[luckv]

I(f zxing is not moved to maven, then this project is at risk of being abandoned... not good I don't like this thing https://github.com/zxing/zxing/#project-in-maintenance-mode-only