chore(deps): bump ember-auto-import from 1.2.19 to 1.2.21

Bumps [ember-auto-import](https://github.com/ef4/ember-auto-import) from 1.2.19 to 1.2.21.
- [Release notes](https://github.com/ef4/ember-auto-import/releases)
- [Changelog](https://github.com/ef4/ember-auto-import/blob/master/CHANGELOG.md)
- [Commits](embroider-build/ember-auto-import@v1.2.19...v1.2.21)

Signed-off-by: dependabot[bot] <support@dependabot.com>

yarn.lock

@@ -3639,9 +3639,9 @@ ember-assign-polyfill@^2.6.0:
     ember-cli-version-checker "^2.0.0"
 
 ember-auto-import@^1.2.19:
-  version "1.2.19"
-  resolved "https://registry.yarnpkg.com/ember-auto-import/-/ember-auto-import-1.2.19.tgz#69a2da0d2c16ab88989c51381c415214e85d1af3"
-  integrity sha512-OT7I3zrIAv/rbbYJFZNqfJi/2HpAscjOWOaBPPUj8VkUnY26HlLO6mSzDIkoUOaTAEWiy2GzjenHGj6b9rivxw==
+  version "1.2.21"
+  resolved "https://registry.yarnpkg.com/ember-auto-import/-/ember-auto-import-1.2.21.tgz#e02ded183844faba66c3f2af97028ef35175b837"
+  integrity sha512-coHnqO3mRnlj/JAQSQBEqzX2wL8rH5YrfEJMzk1102X9MdSX1CWeaUYBcyjvI/pG8fHUhv+4VsD6rQuhTUyZUQ==
   dependencies:
     "@babel/core" "^7.1.6"
     "@babel/traverse" "^7.1.6"
@@ -3656,8 +3656,8 @@ ember-auto-import@^1.2.19:
     ember-cli-babel "^6.6.0"
     enhanced-resolve "^4.0.0"
     fs-extra "^6.0.1"
-    fs-tree-diff "^0.5.7"
-    handlebars "^4.0.11"
+    fs-tree-diff "^1.0.0"
+    handlebars "~4.0.13"
     js-string-escape "^1.0.1"
     lodash "^4.17.10"
     mkdirp "^0.5.1"
@@ -3666,7 +3666,7 @@ ember-auto-import@^1.2.19:
     rimraf "^2.6.2"
     symlink-or-copy "^1.2.0"
     walk-sync "^0.3.3"
-    webpack "^4.12.0"
+    webpack "~4.28"
 
 ember-cli-babel@^6.0.0-beta.4, ember-cli-babel@^6.0.0-beta.7, ember-cli-babel@^6.16.0, ember-cli-babel@^6.6.0, ember-cli-babel@^6.8.1, ember-cli-babel@^6.8.2:
   version "6.18.0"
@@ -5405,6 +5405,17 @@ handlebars@^4.0.11, handlebars@^4.0.4, handlebars@^4.0.6:
   optionalDependencies:
     uglify-js "^3.1.4"
 
+handlebars@~4.0.13:
+  version "4.0.13"
+  resolved "https://registry.yarnpkg.com/handlebars/-/handlebars-4.0.13.tgz#89fc17bf26f46fd7f6f99d341d92efaae64f997d"
+  integrity sha512-uydY0jy4Z3wy/iGXsi64UtLD4t1fFJe16c/NFxsYE4WdQis8ZCzOXUZaPQNG0e5bgtLQV41QTfqBindhEjnpyQ==
+  dependencies:
+    async "^2.5.0"
+    optimist "^0.6.1"
+    source-map "^0.6.1"
+  optionalDependencies:
+    uglify-js "^3.1.4"
+
 has-ansi@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/has-ansi/-/has-ansi-2.0.0.tgz#34f5049ce1ecdf2b0649af3ef24e45ed35416d91"
@@ -9981,7 +9992,7 @@ webpack-sources@^1.1.0, webpack-sources@^1.3.0:
     source-list-map "^2.0.0"
     source-map "~0.6.1"
 
-webpack@^4.12.0:
+webpack@~4.28:
   version "4.28.4"
   resolved "https://registry.yarnpkg.com/webpack/-/webpack-4.28.4.tgz#1ddae6c89887d7efb752adf0c3cd32b9b07eacd0"
   integrity sha512-NxjD61WsK/a3JIdwWjtIpimmvE6UrRi3yG54/74Hk9rwNj5FPkA4DJCf1z4ByDWLkvZhTZE+P3C/eh6UD5lDcw==