docs: add release notes for v5.5.0

Author: github-actions[bot]

release_notes/v5.5.0.md

@@ -0,0 +1,16 @@
+# [5.5.0](https://github.com/NHSDigital/eps-common-workflows/compare/v5.4.5...v5.5.0) (2026-02-20)
+
+
+### New
+
+* [AEA-0000] - Use pre-built devcontainer (#66) ([36677e1](https://github.com/NHSDigital/eps-common-workflows/commit/36677e1d6bfaa010d7b78942a1ade12fbefecb80))
+
+
+
+
+## Info
+[Release workflow run](https://github.com/NHSDigital/eps-common-workflows/actions/runs/22231749611) - Workflow ID: 22231749611
+
+It was initialized by [anthony-nhs](https://github.com/anthony-nhs)
+
+