Fix CI

Author: qchateau

.github/workflows/tests.yml

@@ -1,6 +1,10 @@
 name: tests
 
-on: push
+on:
+  push:
+  pull_request:
+    branches:
+      - master
 
 jobs:
   build:
@@ -43,7 +47,7 @@ jobs:
       - uses: actions/setup-python@v1
 
       - name: Install dependencies
-        run: python -m pip install -U conan conan_package_tools
+        run: python -m pip install -U "conan<2" conan_package_tools
 
       - name: Install Ubuntu compilers
         if: matrix.os == 'ubuntu-22.04'