fix(@angular/cli): exclude @angular/material@7.x from ng add package discovery

`@angular/material@7.x` uses unbounded ranges for its framework peer dependencies.
This can cause `ng add` to pick these versions of the package if the newer versions
are not compatible since the peer dependency ranges would match any newer stable
framework version.

Author: clydin

packages/angular/cli/src/commands/add/cli.ts

@@ -50,6 +50,8 @@ interface AddCommandArgs extends SchematicsCommandArgs {
 const packageVersionExclusions: Record<string, string | undefined> = {
   // @angular/localize@9.x versions do not have peer dependencies setup
   '@angular/localize': '9.x',
+  // @angular/material@7.x versions have unbounded peer dependency ranges (>=7.0.0)
+  '@angular/material': '7.x',
 };
 
 export class AddCommandModule