Add missing 'apt' dependency for puppet_agent

[gavindidrichsen]

Before the change notice the UNMET DEPENDENCY puppetlabs-apt (>= 7.7.1 < 10.0.0) beneath the puppet_agent:

➜  puppet-gitea git:(main) ✗ bera spec_prep
+ bundle exec rake spec_prep
==> rake spec_prep
...
...
➜  puppet-gitea git:(main) ✗ puppet module list --tree --modulepath=spec/fixtures/modules
Warning: Missing dependency 'puppetlabs-apt':
  'puppetlabs-puppet_agent' (v4.20.0) requires 'puppetlabs-apt' (>= 7.7.1 < 10.0.0)
/Users/gavin.didrichsen/@REFERENCES/github/app/parent/tools/gitea/forks/puppet-gitea/spec/fixtures/modules
├─┬ h0tw1r3-gitea (v3.2.0)
│ ├── puppetlabs-stdlib (v9.6.0)
│ ├── puppetlabs-inifile (v6.1.1)
│ ├── puppet-archive (v7.1.0)
│ ├── puppet-extlib (v7.0.0)
│ └── puppet-systemd (v7.0.0)
├─┬ puppetlabs-puppet_agent (v4.20.0)
│ ├── UNMET DEPENDENCY puppetlabs-apt (>= 7.7.1 < 10.0.0)
│ └── puppetlabs-facts (v1.5.0)
└── puppetlabs-provision (v2.1.1)
➜  puppet-gitea git:(main) ✗ 

After the change

➜  puppet-gitea git:(main) ✗ puppet module list --tree --modulepath=spec/fixtures/modules
/Users/gavin.didrichsen/@REFERENCES/github/app/parent/tools/gitea/forks/puppet-gitea/spec/fixtures/modules
├─┬ h0tw1r3-gitea (v3.2.0)
│ ├── puppetlabs-stdlib (v9.6.0)
│ ├── puppetlabs-inifile (v6.1.1)
│ ├── puppet-archive (v7.1.0)
│ ├── puppet-extlib (v7.0.0)
│ └── puppet-systemd (v7.0.0)
├─┬ puppetlabs-puppet_agent (v4.20.0)
│ ├── puppetlabs-apt (v9.4.0)
│ └── puppetlabs-facts (v1.5.0)
└── puppetlabs-provision (v2.1.1)
➜  puppet-gitea git:(main) ✗