Fix nightly build by moving tf2.4.1 to Python3.7 (#1611)

Signed-off-by: Tom Wildenhain <[email protected]>

Author: TomWildenhain-Microsoft

ci_build/azure_pipelines/onnxruntime_nightly_test.yml

@@ -51,12 +51,24 @@ stages:
           steps:
           - template: 'unit_test.yml'
         report_coverage: 'True'
+
+    - template: 'templates/job_generator.yml'
+      parameters:
+        platforms: ['linux']
+        python_versions: ['3.7']
+        tf_versions: ['2.4.1']
+        onnx_opsets: ['']
+        onnx_backends: {onnxruntime: ['nightly']}
+        job:
+          steps:
+          - template: 'unit_test.yml'
+        report_coverage: 'True'
 
     - template: 'templates/job_generator.yml'
       parameters:
         platforms: ['linux']
         python_versions: ['3.9']
-        tf_versions: ['2.5.0', '2.4.1']
+        tf_versions: ['2.5.0']
         onnx_opsets: ['']
         onnx_backends: {onnxruntime: ['nightly']}
         job: