Revert "contrib/jenkins.sh: pylint v2.15 is unstable, pin v2.14.5"

This reverts commit 12175d358850cfbfe40c060292d8273cabc23cbc.

The upstream has fixed the regression:

https://github.com/PyCQA/pylint/issues/7375

which was actually not in pylint itself but in its dependency:

https://github.com/PyCQA/astroid/pull/1763
https://github.com/PyCQA/astroid/releases/tag/v2.12.6

Change-Id: I1bf36e0c6db14a10ff4eab57bae238401dbd7fd0
Closes: OS#5668
diff --git a/contrib/jenkins.sh b/contrib/jenkins.sh
index a061c7e..fbcd73c 100755
--- a/contrib/jenkins.sh
+++ b/contrib/jenkins.sh
@@ -26,7 +26,7 @@
 # Ignore E0401: import-error
 #   pySim/utils.py:276: E0401: Unable to import 'Crypto.Cipher' (import-error)
 #   pySim/utils.py:277: E0401: Unable to import 'Crypto.Util.strxor' (import-error)
-pip install pylint==2.14.5 # FIXME: 2.15 is crashing, see OS#5668
+pip install pylint
 python -m pylint -j0 --errors-only \
 	--disable E1102 \
 	--disable E0401 \