MINOR: [R] Add 21.0.0.1 and 22.0.0 to compatiblity matrix (#48077)

### Rationale for this change

CI needs updating to test old R package versions

### What changes are included in this PR?

Add 21.0.0.1 and 22.0.0 to compatibility matrix

### Are these changes tested?

Nah, it's CI stuff

### Are there any user-facing changes?

Nope

Authored-by: Nic Crane <[email protected]>
Signed-off-by: Nic Crane <[email protected]>

Author: thisisnic

dev/tasks/r/github.linux.arrow.version.back.compat.yml

@@ -73,6 +73,8 @@ jobs:
         config:
         # We use the R version that was released at the time of the arrow release in order
         # to make sure we can download binaries from RSPM.
+        - { old_arrow_version: '22.0.0', r: '4.5' }
+        - { old_arrow_version: '21.0.0.1', r: '4.5' }
         - { old_arrow_version: '20.0.0.2', r: '4.5' }
         - { old_arrow_version: '20.0.0', r: '4.5' }
         - { old_arrow_version: '19.0.1', r: '4.4' }