Regular expression for matching black exe version is not valid for old black release

[jpraet]

The regular expression was modified in #1178 to match the new version format, but no longer works for the previous format.

10:29:19  [ERROR] Failed to execute goal com.diffplug.spotless:spotless-maven-plugin:2.22.4:apply (default) on project buildtools: Execution default of goal com.diffplug.spotless:spotless-maven-plugin:2.22.4:apply failed: You specified version 19.10b0, but Spotless found version
10:29:19  [ERROR] Try running {@code pip install --force-reinstall black==19.10b0}, or else specify {@code black('version')} to Spotless
10:29:19  [ERROR]   github issue to handle this better: https://github.com/diffplug/spotless/issues/674
10:29:19  [ERROR] > arguments: [/usr/local/bin/black, --version]
10:29:19  [ERROR] > exit code: 0
10:29:19  [ERROR] >    stdout: black, version 19.10b0
10:29:19  [ERROR] >    stderr: (empty)
10:29:19  [ERROR] -> [Help 1]

• Apache Maven 3.8.4
• spotless-maven-plugin 2.22.4

[nedtwigg]

Fixed in plugin-gradle 6.6.0 and plugin-maven 2.22.5.