copr: Also install git

This whole "install all the build tools to make a source rpm"
flow rather stinks...

One thing that would help is for me (or someone else) to package
cargo-vendor-filterer at some point.

Signed-off-by: Colin Walters <walters@verbum.org>

.copr/Makefile

@@ -1,5 +1,5 @@
 srpm:
-	dnf -y install dnf-utils
+	dnf -y install dnf-utils git
 	dnf -y builddep bootc
 	# similar to https://github.com/actions/checkout/issues/760, but for COPR
 	git config --global --add safe.directory '*'