Fix a meson warning about using the deprecated python3 feature

Signed-off-by: David Boddie <david.boddie@puri.sm>
10 jobs for !966 with fix-python3-meson-warning in 15 minutes and 52 seconds (queued for 3 seconds)
latest detached
Status Job ID Name Coverage
  Containers Build
passed debian #324312

00:05:19

 
  Build+Test
passed meson-clang #324314

00:10:30

passed meson-clover #324318

00:09:27

passed meson-main #324317

00:05:58

passed meson-swr-glvnd #324313

00:07:40

passed meson-vulkan #324319

00:02:44

passed scons-llvm #324321

00:07:49

passed scons-nollvm #324320

00:03:29

passed scons-swr #324315

00:06:40

passed scons-win64 #324316

00:06:59