Bump lowest versions in pip requirements

requirements-dev.txt

@@ -4,8 +4,8 @@
 
 -r requirements.txt
 pycodestyle>=2.5.0
-pylint>=2.3.1
-pytest>=4.6.2
-pytest-cov>=2.7.1
-pytest-mock>=1.11.0
-requests_mock>=1.6.0
+pylint>=2.4.2
+pytest>=5.2.1
+pytest-cov>=2.8.1
+pytest-mock>=1.11.1
+requests_mock>=1.7.0

requirements.txt

@@ -2,5 +2,5 @@
 # SPDX-License-Identifier: AGPL-3.0-only
 # License-Filename: LICENSE.md
 
-requests2>=2.16
-websockets>=7.0
+requests2>=2.16.0
+websockets>=8.0.2