add environment file

Author: wolfv

.github/micromamba_ci_environment.yml

@@ -0,0 +1,8 @@
+name: ci_environment
+channels:
+  - conda-forge
+dependencies:
+  - c-compiler
+  - ninja
+  - cmake
+  - zlib

.github/workflows/ci.yml

@@ -35,12 +35,7 @@ jobs:
       - uses: actions/checkout@v2
       - name: Install environment from environment.yml
         uses: mamba-org/provision-with-micromamba@main
-        with:
-          extra-specs: |
-            c-compiler
-            ninja
-            cmake
-            zlib
+        environment-file: .github/micromamba_ci_environment.yml
 
       - name: Build
         run:  |