Add is:pull-request to search query when looking for existing PR (#228)

* Add `is:pull-request` to search query when looking for existing PR

* Create sharp-pens-matter.md

* Update .changeset/sharp-pens-matter.md

Co-authored-by: Mateusz Burzyński <mateuszburzynski@gmail.com>

.changeset/sharp-pens-matter.md

@@ -0,0 +1,5 @@
+---
+"@changesets/action": patch
+---
+
+Add `is:pull-request` to search query when looking for existing PR. This fixes an issue with user-owned PATs.

src/run.ts

@@ -291,7 +291,7 @@ export async function runVersion({
     });
   }
 
-  let searchQuery = `repo:${repo}+state:open+head:${versionBranch}+base:${branch}`;
+  let searchQuery = `repo:${repo}+state:open+head:${versionBranch}+base:${branch}+is:pull-request`;
   let searchResultPromise = octokit.search.issuesAndPullRequests({
     q: searchQuery,
   });