Fix 175: added template filter to update copyright year.

[HPNavjot]

Fix #175

Changes:

• Updated template files to use the new copyright_period filter.
• Changes in genTypes script to look into git history and fetch creation date of existing file.
• Set current year is default copyright recent change year.
• Added argument to override default copyright recent change year. -- User can pass custom copyright year using -y or --Year argument i.e. python genTypes.py -y 2023.