tuna: Switch to PEP-517 build backend

The project has a proper pyproject.toml which declares the
setuptools.build.meta PEP-517 backend.

Fixes
WARNING: tuna-0.20-r0 do_check_backend: QA Issue: inherits setuptools3 but has pyproject.toml with setuptools.build_meta, use the correct class [pep517-backend]

Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-python/recipes-extended/tuna/tuna_0.20.bb

@@ -15,7 +15,7 @@ RDEPENDS:${PN} += " \
     python3-six \
     "
 
-inherit setuptools3
+inherit python_setuptools_build_meta
 
 do_install:append() {
     install -m 0755 -d ${D}${bindir}