Update CI_build.yml

.github/workflows/CI_build.yml

@@ -8,14 +8,14 @@ on:
 jobs:
 
   first_check:
-    name: first code check / python-3.8 / ubuntu-latest
+    name: first code check / python-3.9 / ubuntu-latest
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
       - name: Set up Python
         uses: actions/setup-python@v1
         with:
-          python-version: 3.8
+          python-version: 3.9
       - name: Python info
         run: |
           which python
@@ -53,10 +53,10 @@ jobs:
       fail-fast: false
       matrix:
         os: ['ubuntu-latest', 'macos-latest', 'windows-latest']
-        python-version: ['3.7', '3.8', '3.9']
+        python-version: ['3.9']
         exclude:
           # already tested in first_check job
-          - python-version: 3.8
+          - python-version: 3.9
             os: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
@@ -108,7 +108,7 @@ jobs:
           echo "The code is sufficiently documented with ${UNCOVERED_MEMBERS} uncovered members out of ${UNCOVERED_MEMBERS_ALLOWED} allowed.";
 
   anaconda_build:
-    name: Anaconda build / python-3.7 / ubuntu-latest
+    name: Anaconda build / python-3.9 / ubuntu-latest
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
@@ -123,7 +123,7 @@ jobs:
           activate-environment: spec2vec-build
           auto-update-conda: true
           environment-file: conda/environment-build.yml
-          python-version: 3.8
+          python-version: 3.9
       - name: Show conda config
         shell: bash -l {0}
         run: |