CI: Detect duplicate versions in the CHANGELOG (#402)

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- [x] Does not require a CHANGELOG entry

.github/changelog-processor.py

@@ -45,6 +45,8 @@
     lines = changelog.readlines()
 
     if args.validate_changelog:
+        versions = set()
+
         for line in lines:
             if line.startswith("##"):
                 if line.startswith("###"):
@@ -57,6 +59,13 @@
                     print("Only Major.Minor.Patch are supported as versioning")
                     print(line)
                     sys.exit(-1)
+                else:
+                    version = line.strip().removeprefix("## [").split("]")[0]
+                    if version in versions:
+                        print("Found version '" + version + "' more than once")
+                        sys.exit(-1)
+                    else:
+                        versions.add(version)
             elif line.startswith("#"):
                 if line.strip() != "# Changelog":
                     print("Line starting with `#` is only allowed for `# Changelog`")

CHANGELOG.md

@@ -10,16 +10,6 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 - Kusama: Relay General Admin Origin mapping to xcm Location ([polkadot-fellows/runtimes#383](https://github.com/polkadot-fellows/runtimes/pull/383))
 - Encointer, PeopleKusama, PeoplePolkadot: Configure delivery fees for UMP ([polkadot-fellows/runtimes#390](https://github.com/polkadot-fellows/runtimes/pull/390))
-
-### Changed
-
-- Bounties: Remove payout delay ([polkadot-fellows/runtimes#386](https://github.com/polkadot-fellows/runtimes/pull/386))
-- Polkadot System Chains: Reduce the base transaction fee by half
-
-## [1.2.8] 03.07.2024
-
-### Added
-
 - All runtimes: XcmPaymentApi and DryRunApi ([polkadot-fellows/runtimes#380](https://github.com/polkadot-fellows/runtimes/pull/380))
 
 #### From [#322](https://github.com/polkadot-fellows/runtimes/pull/322):
@@ -50,6 +40,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ### Changed
 
+- Bounties: Remove payout delay ([polkadot-fellows/runtimes#386](https://github.com/polkadot-fellows/runtimes/pull/386))
+- Polkadot System Chains: Reduce the base transaction fee by half
+
 #### From [#322](https://github.com/polkadot-fellows/runtimes/pull/322):
 
 - AdaptPrice trait is now price controlled ([SDK v1.13 #4521](https://github.com/paritytech/polkadot-sdk/pull/4521)).