Update dependency python-dotenv to v0.20.0

requirements.txt

@@ -21,7 +21,7 @@ pyasn1-modules==0.2.8; python_version >= "2.7" and python_full_version < "3.0.0"
 pyasn1==0.4.8; python_version >= "3.5" and python_full_version < "3.0.0" and python_version < "4" and (python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.6.0" and python_version >= "3.6") or python_version >= "3.5" and python_version < "4" and (python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.6.0" and python_version >= "3.6") and python_full_version >= "3.6.0"
 pycparser==2.20; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.6.0" and python_version >= "3.6"
 pyparsing==2.4.7; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.6.0" and python_version >= "3.6"
-python-dotenv==0.15.0
+python-dotenv==0.20.0
 pytz==2021.1; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.6.0" and python_version >= "3.6"
 requests==2.25.1; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.6.0" and python_version >= "3.6"
 rsa==4.7.1; python_version >= "3.5" and python_version < "4" and (python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.6.0" and python_version >= "3.6")