docs: add release notes for v12.0.0 to CHANGELOG
docs: add release notes for v12.0.0 to CHANGELOG

brandonroberts/angular,brandonroberts/angular,gkalpak/angular,shairez/angular,mgechev/angular,angular-indonesia/angular,angular-indonesia/angular,ocombe/angular,JiaLiPassion/angular,ocombe/angular,mgechev/angular,angular/angular,ocombe/angular,shairez/angular,ocombe/angular,JiaLiPassion/angular,angular-indonesia/angular,brandonroberts/angular,JiaLiPassion/angular,manekinekko/angular,ocombe/angular,manekinekko/angular,mgechev/angular,ocombe/angular,gkalpak/angular,angular/angular,angular/angular,manekinekko/angular,angular/angular,gnomeontherun/angular,JiaLiPassion/angular,gnomeontherun/angular,shairez/angular,mgechev/angular,shairez/angular,gkalpak/angular,mgechev/angular,gnomeontherun/angular,brandonroberts/angular,gkalpak/angular,brandonroberts/angular,angular-indonesia/angular,manekinekko/angular,manekinekko/angular,shairez/angular,manekinekko/angular,gnomeontherun/angular,brandonroberts/angular