POSIX compliance edit

http_check_telegram

@@ -7,14 +7,14 @@ CONFIG=$1
 ### Provides KEY, CHATID, CHKLIST
 if [ -n "$CONFIG" ]; then
     if [ -f "$CONFIG" ]; then
-        source $CONFIG
+        . $CONFIG #Source config file
     else
         printf '%s\n' "$CONFIG: File does not exist." >&2
         exit 10
     fi
 else
     if [ -f ".httpcheck_telegram" ]; then
-        source .httpcheck_telegram
+        . .httpcheck_telegram #Source config file
     else
         printf '%s\n' "No configuration file found." >&2
         exit 10