fix: use last-release-sha to ignore problematic commits

Replace bootstrap-sha (only used for first release) with last-release-sha
which is always respected. This tells Release Please to start gathering
commits from d31389c (the last release commit) and ignore the empty
feat(eds-icons) commit that was incorrectly bumping all packages.

Note: Remove last-release-sha after next successful release PR is merged.

Author: pomfrida

.github/release-please-config.json

@@ -1,6 +1,6 @@
 {
   "$schema": "https://raw.githubusercontent.com/googleapis/release-please/main/schemas/config.json",
-  "bootstrap-sha": "d31389cb",
+  "last-release-sha": "d31389cbd96f497b7f96e59821e8dd221945ab62",
   "tag-separator": "@",
   "packages": {
     "packages/eds-core-react": {