Update ChangeLog for v7.1.2 release (#14783)
Update ChangeLog for v7.1.2 release (#14783)

Update ChangeLog for v7.1.2 release

Co-authored-by: Dongbo Wang <a97d1d57b1daa4a18fec44146d68c2c4093535ae@microsoft.com>
daxian-dbw/PowerShell,TravisEz13/PowerShell,daxian-dbw/PowerShell,daxian-dbw/PowerShell,PaulHigin/PowerShell,PaulHigin/PowerShell,TravisEz13/PowerShell,JamesWTruher/PowerShell-1,PaulHigin/PowerShell,JamesWTruher/PowerShell-1,TravisEz13/PowerShell,PaulHigin/PowerShell,daxian-dbw/PowerShell,JamesWTruher/PowerShell-1,JamesWTruher/PowerShell-1,TravisEz13/PowerShell