ci: install systemd-rpm-macros in make-rpm job

greenboot-rs.spec has an unconditional BuildRequires: systemd-rpm-macros,
but the make-rpm job's dnf install step never installs it, only
git/make/rpm-build/rust-toolset. rpmbuild then fails dependency
resolution before it ever gets to building anything:

  error: Failed build dependencies:
      systemd-rpm-macros is needed by greenboot-rs-0.16.3-0.el9.x86_64

Verified by running the exact dnf install + make rpm sequence against
quay.io/centos/centos:stream9 (the job's own container image): with
systemd-rpm-macros added, dnf resolves it straight from CentOS Stream 9
BaseOS/AppStream with no extra repo, and make rpm completes and
produces all four expected RPMs.

Assisted-by: OpenCode (Claude Sonnet 5)

Author: miabbott

.github/workflows/comment-ci.yaml

@@ -59,7 +59,7 @@ jobs:
 
       - name: Build RPMs
         run: |
-          dnf install -y git make rpm-build rust-toolset
+          dnf install -y git make rpm-build rust-toolset systemd-rpm-macros
           make rpm
 
       - name: Verify RPMs were created

.github/workflows/greenboot-ci.yaml

@@ -59,7 +59,7 @@ jobs:
 
       - name: Build RPMs
         run: |
-          dnf install -y git make rpm-build rust-toolset
+          dnf install -y git make rpm-build rust-toolset systemd-rpm-macros
           git config --global --add safe.directory /__w/greenboot-rs/greenboot-rs
           make rpm