Switch to using HTTPS instead of FTP

HTML scraping isn't ideal, but is way faster and hopefully is more reliable and puts us on the correct side of the notice on https://ftp.gnu.org/:

    NOTICE (Updated October 15 2021):

    If you maintain scripts used to access ftp.gnu.org over FTP,
    we strongly encourage you to change them to use HTTPS instead.

    Eventually we hope to shut down FTP protocol access, but plan
    to give notice here and other places for several months ahead
    of time.

versions.sh

@@ -12,14 +12,11 @@ else
 fi
 versions=( "${versions[@]%/}" )
 
-ftpBase='ftp://ftp.gnu.org/gnu/bash'
-ftp_list() {
-	curl --silent --list-only "$ftpBase/${1:-}/"
-}
+ftpBase='https://ftp.gnu.org/gnu/bash'
 
 allBaseVersions="$(
-	ftp_list \
-		| sed -rne '/^bash-([0-9].+)[.]tar[.]gz$/s//\1/p' \
+	wget -qO- "$ftpBase/" \
+		| sed -rne '/^(.*[/"[:space:]])?bash-([0-9].+)[.]tar[.]gz([/"[:space:]].*)?$/s//\2/p' \
 		| sort -V
 )"
 
@@ -84,10 +81,9 @@ for version in "${versions[@]}"; do
 	patchlevel=
 	if [ "$version" = "$rcVersion" ]; then
 		patchlevel="$(
-			ftp_list "bash-$rcVersion-patches" \
-				| sed -rne '/^bash[0-9]+-([0-9]{3})$/s//\1/p' \
-				| tail -1 \
-				|| :
+			{ wget -qO- "$ftpBase/bash-$rcVersion-patches/" || :; } \
+				| sed -rne '/^(.*[/"[:space:]])?bash[0-9]+-([0-9]{3})([/"[:space:]].*)?$/s//\2/p' \
+				| tail -1
 		)"
 	fi
 	patchlevel="${patchlevel#0}"