bibtex2html: update homepage/master_sites to GitHub, fix livecheck

textproc/bibtex2html/Portfile

@@ -16,8 +16,11 @@ long_description    bibtex2html is a collection of tools for \
     produce, from a set of bibliography files in \
     BibTeX format, a bibliography in HTML format.
 
-homepage            https://www.lri.fr/~filliatr/bibtex2html/
-master_sites        http://www.lri.fr/~filliatr/ftp/bibtex2html
+homepage            https://github.com/backtracking/bibtex2html
+# Upstream moved from lri.fr to GitHub. The 1.99 release is tagged "v-1-99"
+# (unlike the earlier v1.98/v1.97 tags), so the download directory is pinned.
+# Unclear if this is a new pattern; we'll see with the next release...
+master_sites        https://github.com/backtracking/bibtex2html/releases/download/v-1-99/
 
 checksums           rmd160  63bec08dcbdb531b4fd233575dd156520ffbfd3c \
                     sha256  d224dadd97f50199a358794e659596a3b3c38c7dc23e86885d7b664789ceff1d \
@@ -41,3 +44,7 @@ destroot.target     install
 destroot.destdir    prefix=${destroot}${prefix}
 
 universal_variant   no
+
+livecheck.type      regex
+livecheck.url       https://api.github.com/repos/backtracking/bibtex2html/releases/latest
+livecheck.regex     {bibtex2html-([0-9.]+)\.tar\.gz}