swtich to require a minimum version for required packages

- use >= instead of == for required python packages

requirements/base.txt

@@ -1,8 +1,8 @@
-Click==7.0
+Click>=7.0
 prompt-toolkit>=3.0.2
-pyaml==19.4.1
-PyYAML==5.1.2
+pyaml>=19.4.1
+PyYAML>=5.1.2
 Pygments>=2.6.0
-SQLAlchemy==1.3.11
-tabulate==0.8.5
+SQLAlchemy>=1.3.11
+tabulate>=0.8.5
 wheel>=0.35.0