Update README.md

Author: DissectMalware

README.md

@@ -31,7 +31,7 @@ xlmdeobfuscator --file document.xlsm
 # Usage
 
 ```
-usage: xlmdeobfuscator [-h] [-f FILE] [-n] [-x] [-2] [-s]
+usage: xlmdeobfuscator [-h] [-f FILE] [-n] [-x] [-2] [-s] [-d DAY]
 
 optional arguments:
   -h, --help              show this help message and exit
@@ -41,6 +41,7 @@ optional arguments:
   -2, --no-ms-excel       Do not use MS Excel to process XLS files
   -s, --start-with-shell  Open an XLM shell before interpreting the macros in
                           the input
+  -d DAY, --day DAY     Specify the day of month
 ```
 
 Read requirements.txt to get the list of python libraries that XLMMacroDeobfuscator is dependent on.