[hack] temporary disable macos-latest

- github workflow executor has transitionned to Apple Silicon M3
- bioconda is available as opt-in on ARM64
- we haven't tested V-pipe on Aarch64 yet

.github/workflows/run_regression_tests.yaml

@@ -64,7 +64,7 @@ jobs:
       max-parallel: 5
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os: [ubuntu-latest, macos-13] # , macos-latest] # disable until V-pipe's support for aarch64 is checked
         python-version: ["3.10", "3.11"]
         virus: ["hiv", "sars-cov-2"]