fix: improve zulu regex to ignore zre links

[andrecloutier]

Fixes: #89

Looks like despite the previous improvement to remove the zre build links, they've somehow made their way back in. This PR improves the grep expression to expect a number following "zulu" in order to avoid the zre or other potentially malformed names.

Before:

root@andrecloutier:~# grep -o -E '<a href=".*/(zulu.+-(linux|macosx|win|solaris)_(musl_x64|musl_aarch64|x64|i686|aarch32hf|aarch32sf|aarch64|ppc64|sparcv9)\.(tar\.gz|zip|msi|dmg))">' "${INDEX_FILE}" | perl -pe 's#<a href=".*/(zulu[^/]+)">#$1#g' | head
<a href="/zulu/bin/zre9.0.0.15-jre9.0.0-macosx_x64.dmg">
<a href="/zulu/bin/zre9.0.0.15-jre9.0.0-macosx_x64.tar.gz">
<a href="/zulu/bin/zre9.0.0.15-jre9.0.0-macosx_x64.zip">
<a href="/zulu/bin/zre9.0.0.15-jre9.0.0-win_x64.msi">
zulu10.1+11-jdk10-linux_i686.zip
zulu10.1+11-jdk10-linux_x64.tar.gz
zulu10.1+11-jdk10-macosx_x64.dmg
zulu10.1+11-jdk10-macosx_x64.tar.gz
zulu10.1+11-jdk10-macosx_x64.zip
zulu10.1+11-jdk10-win_i686.zip

root@andrecloutier:~# grep -o -E '<a href=".*/(zulu.+-(linux|macosx|win|solaris)_(musl_x64|musl_aarch64|x64|i686|aarch32hf|aarch32sf|aarch64|ppc64|sparcv9)\.(tar\.gz|zip|msi|dmg))">' "${INDEX_FILE}" | perl -pe 's#<a href=".*/(zulu[^/]+)">#$1#g' | wc -l
10494

After:

root@andrecloutier:~# grep -o -E '<a href=".*/(zulu[0-9]+.+-(linux|macosx|win|solaris)_(musl_x64|musl_aarch64|x64|i686|aarch32hf|aarch32sf|aarch64|ppc64|sparcv9)\.(tar\.gz|zip|msi|dmg))">' "${INDEX_FILE}" | perl -pe 's#<a href=".*/(zulu[^/]+)">#$1#g' | head
zulu10.1+11-jdk10-linux_i686.zip
zulu10.1+11-jdk10-linux_x64.tar.gz
zulu10.1+11-jdk10-macosx_x64.dmg
zulu10.1+11-jdk10-macosx_x64.tar.gz
zulu10.1+11-jdk10-macosx_x64.zip
zulu10.1+11-jdk10-win_i686.zip
zulu10.1+11-jdk10-win_x64.msi
zulu10.1+11-jdk10-win_x64.zip
zulu10.1+11-jdk10.0.0-linux_i686.zip
zulu10.1+11-jdk10.0.0-linux_x64.tar.gz

root@andrecloutier:~# grep -o -E '<a href=".*/(zulu[0-9]+.+-(linux|macosx|win|solaris)_(musl_x64|musl_aarch64|x64|i686|aarch32hf|aarch32sf|aarch64|ppc64|sparcv9)\.(tar\.gz|zip|msi|dmg))">' "${INDEX_FILE}" | perl -pe 's#<a href=".*/(zulu[^/]+)">#$1#g' | wc -l
10490

[joschi]

@andrecloutier Thanks for fixing this bug!