Simplify getChangelogEntry (#632)

Author: bluwy

.changeset/green-cougars-listen.md

@@ -0,0 +1,5 @@
+---
+"@changesets/action": patch
+---
+
+Simplify internal implementation to get changelog entries for a package version

package.json

@@ -26,12 +26,7 @@
     "@manypkg/get-packages": "^1.1.3",
     "@octokit/core": "^7.0.6",
     "@octokit/plugin-throttling": "^11.0.3",
-    "@types/mdast": "^3.0.15",
-    "mdast-util-to-string": "^1.1.0",
-    "remark-parse": "^7.0.2",
-    "remark-stringify": "^7.0.4",
-    "semver": "^7.8.0",
-    "unified": "^8.4.2"
+    "semver": "^7.8.0"
   },
   "devDependencies": {
     "@changesets/changelog-github": "^0.7.0",