Use DNF for newer Enterprise Linux

Prior to this commit, the install_package and uninstall_package methods
used Yum for all versions of Red Hat Enterprise Linux. However, RHEL has
used DNF as its default package manager since version 8.

This commit updates those methods to use DNF for RHEL 8, 9, and any
future versions and to explicitly use Yum on RHEL versions 1-7.

lib/beaker/host/unix/pkg.rb

@@ -87,10 +87,10 @@ def install_package(name, cmdline_args = '', version = nil, opts = {})
       execute("zypper --non-interactive --gpg-auto-import-keys in #{name}", opts)
     when /el-4/
       @logger.debug("Package installation not supported on rhel4")
-    when /amazon-2023|fedora-(2[2-9]|3[0-9])/
+    when /amazon-2023|el-(8|9|1[0-9])|fedora-(2[2-9]|3[0-9])/
       name = "#{name}-#{version}" if version
       execute("dnf -y #{cmdline_args} install #{name}", opts)
-    when /cisco|fedora|centos|redhat|eos|el-/
+    when /cisco|fedora|centos|redhat|eos|el-[1-7]-/
       name = "#{name}-#{version}" if version
       execute("yum -y #{cmdline_args} install #{name}", opts)
     when /ubuntu|debian|cumulus|huaweios/
@@ -172,9 +172,9 @@ def uninstall_package(name, cmdline_args = '', opts = {})
       execute("zypper --non-interactive rm #{name}", opts)
     when /el-4/
       @logger.debug("Package uninstallation not supported on rhel4")
-    when /amazon-2023|fedora-(2[2-9]|3[0-9])/
+    when /amazon-2023|el-(8|9|1[0-9])|fedora-(2[2-9]|3[0-9])/
       execute("dnf -y #{cmdline_args} remove #{name}", opts)
-    when /cisco|fedora|centos|redhat|eos|el-/
+    when /cisco|fedora|centos|redhat|eos|el-[1-7]-/
       execute("yum -y #{cmdline_args} remove #{name}", opts)
     when /ubuntu|debian|cumulus|huaweios/
       execute("apt-get purge #{cmdline_args} -y #{name}", opts)