01-main...jc: clean, fast URL/version extraction

How the code works: from JSON take (via `grep -m1 -o`) the line
  "browser_download_url": "https://github.com/kellyjonbrazil/jc/releases/download/v1.23.6/jc_1.23.6-1_amd64.deb"

1. extract the matching key/value pair, excluding the final dquote.
2. remove everything upto and including the first dquote -> URL
3. from the URL, remove everything upto & including /download/v
4. then remove everything from '/' onwards -> version

01-main/packages/jc

@@ -2,9 +2,10 @@ DEFVER=1
 ARCHS_SUPPORTED='amd64'
 get_github_releases 'kellyjonbrazil/jc' 'latest'
 if [ "${ACTION}" != prettylist ]; then
-    URL=$(grep -m1 "browser_download_url.*${HOST_ARCH}.*\.deb\"" "${CACHE_FILE}" | cut -d'"' -f4)
-    VERSION_PUBLISHED=$(sed -n -e 's@.*/download/v\([^/]*\)/.*@\1@p' <<<"$URL")
-    printf %s\\n "$VERSION_PUBLISHED" >/tmp/dg.log
+    URL=$(grep -m1 -o "\"browser_download_url\":[[:space:]]*\"[^\"]*${HOST_ARCH}[^\"]*\.deb" "${CACHE_FILE}")
+    URL=${URL##*\"}
+    VERSION_PUBLISHED=${URL##*/download/v}
+    VERSION_PUBLISHED=${VERSION_PUBLISHED%%/*}
 fi
 EULA=''
 PRETTY_NAME='jc'