chore: release the three packages as one unit, starting with a beta (#208)

The previous config declared each package separately, so merging the release PR
would have created three tags and three draft GitHub Releases. Publishing any
one of them fires publish.yml, which publishes all three packages - so the first
release would have done the whole job and the other two would have failed with
"cannot publish over the previously published versions". The changelog was also
split three ways, with no single place describing the release.

These packages are versioned in lockstep and published together, so they are
one releasable unit. The root is now the only release: one tag, one GitHub
release, one changelog. The three package.json versions are updated through
extra-files, which is what keeps them in step - the workspace: protocol plus
pnpm pack already handles the ranges between them.

Two things fall out of this. The grouped PR title interpolates ${version} again,
because release-please takes it from the release at path "." and there was not
one before. And the tag is v<version>, matching every tag this repo has used
since v4.

Also switches to prerelease versioning, so the next release is 5.1.0-beta
published to the `next` dist-tag. Dropping `prerelease`, `prerelease-type` and
`versioning` from the package graduates it to a stable 5.1.0 on `latest`.

Verified by dry run against this branch:

  ✔ updating from 1.0.0 to 5.1.0-beta
  Would open 1 pull requests
  updates: packages/plugin-rest-cache/package.json,
           packages/provider-rest-cache-memory/package.json,
           packages/provider-rest-cache-redis/package.json,
           CHANGELOG.md, .release-please-manifest.json

Co-authored-by: Claude <noreply@anthropic.com>

Author: derrickmehaffy

.release-please-manifest.json

@@ -1,5 +1,3 @@
 {
-  "packages/plugin-rest-cache": "5.0.1",
-  "packages/provider-rest-cache-memory": "5.0.0",
-  "packages/provider-rest-cache-redis": "5.0.0"
+  ".": "5.0.1"
 }

release-please-config.json

@@ -2,21 +2,8 @@
   "$schema": "https://raw.githubusercontent.com/googleapis/release-please/main/schemas/config.json",
   "release-type": "node",
   "separate-pull-requests": false,
-  "group-pull-request-title-pattern": "chore: release ${version}",
   "pull-request-title-pattern": "chore: release ${version}",
   "draft": true,
-  "prerelease-type": "beta",
-  "plugins": [
-    {
-      "type": "linked-versions",
-      "groupName": "rest-cache",
-      "components": [
-        "plugin-rest-cache",
-        "provider-rest-cache-memory",
-        "provider-rest-cache-redis"
-      ]
-    }
-  ],
   "changelog-sections": [
     {
       "type": "feat",
@@ -63,14 +50,29 @@
     }
   ],
   "packages": {
-    "packages/plugin-rest-cache": {
-      "component": "plugin-rest-cache"
-    },
-    "packages/provider-rest-cache-memory": {
-      "component": "provider-rest-cache-memory"
-    },
-    "packages/provider-rest-cache-redis": {
-      "component": "provider-rest-cache-redis"
+    ".": {
+      "component": "",
+      "changelog-path": "CHANGELOG.md",
+      "extra-files": [
+        {
+          "type": "json",
+          "path": "packages/plugin-rest-cache/package.json",
+          "jsonpath": "$.version"
+        },
+        {
+          "type": "json",
+          "path": "packages/provider-rest-cache-memory/package.json",
+          "jsonpath": "$.version"
+        },
+        {
+          "type": "json",
+          "path": "packages/provider-rest-cache-redis/package.json",
+          "jsonpath": "$.version"
+        }
+      ],
+      "prerelease": true,
+      "prerelease-type": "beta",
+      "versioning": "prerelease"
     }
   },
   "last-release-sha": "6407e61f4c89863c84e542bc2a92a07801ff4f9a"