Using CalVer for Besu Releases

On 17 Sep 2020 the Hyperledger TSC voted to Allow projects to use CalVer or SemVer.  

General background on Calendar Versioning (CalVer) - https://calver.org/

CalVer taxonomy: YY.M.patch

• YY: Year (20, 21, 22, etc.)
  
• M: Month (1, 2, 3, ..., 11, 12). 
• Patch: Fortnightly releases, or whenever sub-month releases happen.
• YY.M.patch: The year and month are from the current month.

Breaking Changes Policy

• No intentional backwards incompatible breaking changes should occur without 3 months of prior notice via the deprecation policy.
  • Java Plugin APIs
  • CLI flags and configuration files
  • On-disk storage compatibility
  • JSON-RPC APIs
• Patches may introduce forwards compatible changes, such as (but not limited to) new features, new fork or chain support, and new JSON-RPC apis.
• A notice for an intentional breaking change should be in the CHANGELOG.md file for at least 3 months. 
• Examples of such changes:
  • Changing the required JDK.  (such as when we went form Java 17 to Java 21).
  • Removing storage formats, or required migrations.
  • Dropping obsolete CLI flags, such as the whitelist series flags (replaced by the allowlist series)
• This breaking change policy will not prohibit rapid release of security related updates.