package/python-inflection: needs python3

python 2 support has been removed since version 0.4.0 and
https://github.com/jpvanhal/inflection/commit/a826dac7a562e67881ab704adbef45440566836e
resulting in the following build failure since bump to version 0.5.1 in
commit 6c09567e6b6f2cc826e64cd9b36fb41ed7c6e00c:

  File "/home/giuliobenetti/autobuild/run/instance-1/output-1/build/host-python-inflection-0.5.1/inflection/__init__.py", line 91
    def _irregular(singular: str, plural: str) -> None:
                           ^

Propagate host-python3 dependency to host-sdbusplus

Fixes:
 - http://autobuild.buildroot.org/results/6d6e937135ef95c63001359fec5f8c28183fc0a9

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>

package/python-inflection/Config.in

@@ -1,7 +1,7 @@
 config BR2_PACKAGE_PYTHON_INFLECTION
 	bool "python-inflection"
-	select BR2_PACKAGE_PYTHON_UNICODEDATA if BR2_PACKAGE_PYTHON
-	select BR2_PACKAGE_PYTHON3_UNICODEDATA if BR2_PACKAGE_PYTHON3
+	depends on BR2_PACKAGE_PYTHON3
+	select BR2_PACKAGE_PYTHON3_UNICODEDATA
 	help
 	  A string transformation library that singularizes and
 	  pluralizes English words, and transforms strings from

package/sdbusplus/sdbusplus.mk

@@ -10,7 +10,7 @@ SDBUSPLUS_DEPENDENCIES = host-autoconf-archive host-pkgconf systemd
 HOST_SDBUSPLUS_DEPENDENCIES = \
 	host-autoconf-archive \
 	host-pkgconf \
-	$(if $(BR2_PACKAGE_PYTHON3),host-python3,host-python) \
+	host-python3 \
 	host-python-inflection \
 	host-python-mako \
 	host-python-pyyaml