Self hosted runner check could be updated to allow runner* hostnames

[georgemccabe]

The check on this line:

metplus-action-free-disk-space/free-disk-space.sh

Line 43 in 3d293f2

if [[ ! "$hostname" =~ ^(fv-az|fv-az[0-9]|GitHub-Actions-) ]]; then

seems to always fail in GitHub Actions because the hostname doesn't match the expected names. Acceptable names include runner* e.g. runnervm3ublj. This line could be updated to support this naming.