Verify Putty 0.73 Windows Installers

• https://the.earth.li/~sgtatham/putty/latest/w32/putty-0.73-installer.msi.gpg
• https://the.earth.li/~sgtatham/putty/latest/w64/putty-64bit-0.73-installer.msi.gpg
• PuTTY Download Keys and Signatures