Bump the deprecated API version to REv2.2

With support for REv2.0 and REv2.1 specific features removed, we should
go ahead and bump the deprecated API version to REv2.2. This will force
clients to stop using these old features, or simply stop working
altogether.

Author: EdSchouten

pkg/scheduler/in_memory_build_queue.go

@@ -288,14 +288,13 @@ var inMemoryBuildQueueCapabilitiesProvider = capabilities.NewStaticProvider(&rem
 	// - REv2.2 moves the platform properties from Command to Action.
 	// - REv2.3 changes the way Command.arguments[0] is interpreted.
 	//
-	// For some of these features we still support the old behavior
-	// by enabling configuration options in the scheduler and
-	// worker. However, these options will be removed after
-	// 2026-04-01.
+	// We should set the deprecated API version to REv2.3 as well,
+	// as we always process Commands.arguments[0] according to the
+	// new semantics. However, that would break compatibility with
+	// Bazel 8.x and below.
 	//
-	// TODO: Bump the deprecated API version when the legacy options
-	// are removed.
-	DeprecatedApiVersion: &semver.SemVer{Major: 2, Minor: 0},
+	// TODO: Bump the deprecated API version to REv2.3 on 2027-07-01.
+	DeprecatedApiVersion: &semver.SemVer{Major: 2, Minor: 2},
 	LowApiVersion:        &semver.SemVer{Major: 2, Minor: 3},
 	HighApiVersion:       &semver.SemVer{Major: 2, Minor: 11},
 })