adapt path of thirdparty file in ci [run ci]

Author: sandro-elsweijer

.github/workflows/test_preparation.yml

@@ -155,9 +155,9 @@ jobs:
         && echo P4EST_RELEASE=$PWD/p4est/build/Release >> $GITHUB_ENV
     - name: Get p4est commit hash and url from thirdparty.json
       run: |
-        hash=$(jq -r '.thirdparty[] | select(.name=="P4EST") .source.ref' thirdparty.json)
+        hash=$(jq -r '.thirdparty[] | select(.name=="P4EST") .source.ref' cmake/thirdparty.json)
         echo p4est_commit=$hash >> $GITHUB_ENV
-        url=$(jq -r '.thirdparty[] | select(.name=="P4EST") .source.url' thirdparty.json)
+        url=$(jq -r '.thirdparty[] | select(.name=="P4EST") .source.url' cmake/thirdparty.json)
         echo p4est_url=$url >> $GITHUB_ENV
     - name: Check cache for previous p4est installation
       id: p4est_cmake_cache