Bugfix for short IDs that match on two lines

Fix for cases where grep also finds the line starting with sec.
The second line has  the full PGP fingerprint alone.
Therefore, it always ends with the shortened fingerprint.

securitytxt-signer.sh

@@ -120,7 +120,7 @@ else
 
   # Replace PGP IDs with the full PGP fingerprint.
   GREPABLE_KEY=${KEY//0x/}
-  FP=$(echo "$KEY_INFO" | grep -i "$GREPABLE_KEY" | sed -e 's/[^A-F0-9]//g')
+  FP=$(echo "$KEY_INFO" | grep -i "${GREPABLE_KEY}\$" | sed -e 's/[^A-F0-9]//g')
   KEY="0x${FP}"
   if ! [[ "${KEY}" = "0x${GREPABLE_KEY^^}" ]]; then
     echo -e "\033[0;33mEXPANDED 0x${GREPABLE_KEY^^} TO ${KEY}\033[0;0m"