fix: cd into valgrind dir

Author: not-matthias

.github/workflows/codspeed.yml

@@ -38,6 +38,7 @@ jobs:
       - name: Install valgrind
         run: |
           git clone https://github.com/CodSpeedHQ/valgrind-codspeed.git --branch cod-578-fix-span-ordering-on-the-flamegraph
+          cd valgrind-codspeed
           sudo apt-get install -y \
               build-essential \
               automake \