The E2E schematic will now (as it did previously) skip adding dependencies
if they already exist within the `package.json` regardless of the specifier.
This is accomplished with the `existing` option for the `addDependency` rule
which allows defining the behavior for when a dependency already exists.
Currently the two option behaviors are skip and replace with replace being
the default to retain behavior for existing rule usages.
When using the `addDependency` helper rule, a package specifier mismatch will
now result in a warning instead of an error. This prevents the potential
for breaking changes in schematics that previously allowed the behavior.
The warning will also display the existing and new specifiers to better inform
the schematic user of the outcome of the schematic.
When using the `addDependency` rule from `@schematics/angular/utility` a new option is now
available that supports controlling the rule's behavior when scheduling the `NodePackageInstallTask`.
Previously, the behavior was automatic and the rule would only schedule the task if it was not already
scheduled by a previous `addDependency` rule usage for the `package.json`. This behavior is still the
default behavior. However, it can now be customized per rule invocation via the `install` rule option
which can be either `InstallBehavior.None`, `InstallBehavior.Auto`, or `InstallBehavior.Always`.
An `addDependency` schematics rule has been added to the newly introduced `utility` subpath export for the `@schematics/angular` package.
This new rule allows for adding a package as a dependency to a `package.json`. By default the `package.json` located
at the schematic's root will be used. The `packageJsonPath` option can be used to explicitly specify
a `package.json` in a different location. The type of the dependency can also be specified instead
of the default of the `dependencies` section by using the `type` option for either development or peer dependencies.
