build: drop support for python 3.6

python 3.6 EOL was Dec. 2021
buildbot is running debian 10 which ships with 3.7
meson 0.62+ requires 3.7
Signed-off-by: NDoug Kerr <dek3rr@gmail.com>
Signed-off-by: Petr Štetiar <ynezz@true.cz> [rebased]

README.md

@@ -44,7 +44,7 @@ documentation.
 
 ```
 binutils bzip2 diff find flex gawk gcc-6+ getopt grep install libc-dev libz-dev
-make4.1+ perl python3.6+ rsync subversion unzip which
+make4.1+ perl python3.7+ rsync subversion unzip which
 ```
 
 ### Quickstart

include/prereq-build.mk

@@ -175,23 +175,21 @@ $(eval $(call SetupHostCommand,install,Please install GNU 'install', \
 $(eval $(call SetupHostCommand,perl,Please install Perl 5.x, \
 	perl --version | grep "perl.*v5"))
 
-$(eval $(call SetupHostCommand,python,Please install Python >= 3.6, \
+$(eval $(call SetupHostCommand,python,Please install Python >= 3.7, \
 	python3.11 -V 2>&1 | grep 'Python 3', \
 	python3.10 -V 2>&1 | grep 'Python 3', \
 	python3.9 -V 2>&1 | grep 'Python 3', \
 	python3.8 -V 2>&1 | grep 'Python 3', \
 	python3.7 -V 2>&1 | grep 'Python 3', \
-	python3.6 -V 2>&1 | grep 'Python 3', \
-	python3 -V 2>&1 | grep -E 'Python 3\.([6-9]|[0-9][0-9])\.?'))
+	python3 -V 2>&1 | grep -E 'Python 3\.([7-9]|[0-9][0-9])\.?'))
 
-$(eval $(call SetupHostCommand,python3,Please install Python >= 3.6, \
+$(eval $(call SetupHostCommand,python3,Please install Python >= 3.7, \
 	python3.11 -V 2>&1 | grep 'Python 3', \
 	python3.10 -V 2>&1 | grep 'Python 3', \
 	python3.9 -V 2>&1 | grep 'Python 3', \
 	python3.8 -V 2>&1 | grep 'Python 3', \
 	python3.7 -V 2>&1 | grep 'Python 3', \
-	python3.6 -V 2>&1 | grep 'Python 3', \
-	python3 -V 2>&1 | grep -E 'Python 3\.([6-9]|[0-9][0-9])\.?'))
+	python3 -V 2>&1 | grep -E 'Python 3\.([7-9]|[0-9][0-9])\.?'))
 
 $(eval $(call TestHostCommand,python3-distutils, \
 	Please install the Python3 distutils module, \