[github-actions] Add an explicit apt-get update before attempting to install packages on ubuntu
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index aff2502..413513a 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -8,6 +8,7 @@
     steps:
     - name: install dependencies
       run: |
+          sudo apt-get update
           sudo apt-get install cython3
     - name: prepare environment
       run: |