meta/meta-selftest/meta-skeleton: Update LICENSE variable to use SPDX license identifiers

An automated conversion using scripts/contrib/convert-spdx-licenses.py to
convert to use the standard SPDX license identifiers. Two recipes in meta-selftest
were not converted as they're that way specifically for testing. A change in
linux-firmware was also skipped and may need a more manual tweak.

(From OE-Core rev: ceda3238cdbf1beb216ae9ddb242470d5dfc25e0)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/python/python3_3.10.2.bb

@@ -1,7 +1,7 @@
 SUMMARY = "The Python Programming Language"
 HOMEPAGE = "http://www.python.org"
 DESCRIPTION = "Python is a programming language that lets you work more quickly and integrate your systems more effectively."
-LICENSE = "PSFv2"
+LICENSE = "PSF-2.0"
 SECTION = "devel/python"
 
 LIC_FILES_CHKSUM = "file://LICENSE;md5=4b8801e752a2c70ac41a5f9aa243f766"