chore(deps): update dependency ember-cli-showdown to v6

package.json

@@ -35,7 +35,7 @@
     "ember-cli-qunit": "4.4.0",
     "ember-cli-release": "1.0.0-beta.2",
     "ember-cli-shims": "1.2.0",
-    "ember-cli-showdown": "4.5.0",
+    "ember-cli-showdown": "6.0.1",
     "ember-cli-uglify": "3.0.0",
     "ember-composable-helpers": "2.4.0",
     "ember-concurrency": "1.3.0",

yarn.lock

@@ -6895,7 +6895,7 @@ broccoli-output-wrapper@^3.2.5:
     heimdalljs-logger "^0.1.10"
     symlink-or-copy "^1.2.0"
 
-broccoli-persistent-filter@^1.0.3, broccoli-persistent-filter@^1.1.5, broccoli-persistent-filter@^1.1.6, broccoli-persistent-filter@^1.4.2, broccoli-persistent-filter@^1.4.3:
+broccoli-persistent-filter@^1.1.5, broccoli-persistent-filter@^1.1.6, broccoli-persistent-filter@^1.4.2, broccoli-persistent-filter@^1.4.3:
   version "1.4.3"
   resolved "https://registry.yarnpkg.com/broccoli-persistent-filter/-/broccoli-persistent-filter-1.4.3.tgz#3511bc52fc53740cda51621f58a28152d9911bc1"
   integrity sha512-JwNLDvvXJlhUmr+CHcbVhCyp33NbCIAITjQZmJY9e8QzANXh3jpFWlhSFvkWghwKA8rTAKcXkW12agtiZjxr4g==
@@ -8914,16 +8914,6 @@ [email protected]:
     strip-bom "^4.0.0"
     walk-sync "^2.2.0"
 
-ember-cli-htmlbars@^2.0.3:
-  version "2.0.3"
-  resolved "https://registry.yarnpkg.com/ember-cli-htmlbars/-/ember-cli-htmlbars-2.0.3.tgz#e116e1500dba12f29c94b05b9ec90f52cb8bb042"
-  integrity sha512-oyWtJebOwxAqWZwMc0NKFJ8FJdxVixM7zl0FaXq1vTAG6bOgnU7yAhXEASlaO5f+PptZueZfOpdpvRwZW/Gk1A==
-  dependencies:
-    broccoli-persistent-filter "^1.0.3"
-    hash-for-dep "^1.0.2"
-    json-stable-stringify "^1.0.0"
-    strip-bom "^3.0.0"
-
 ember-cli-htmlbars@^5.7.1:
   version "5.7.1"
   resolved "https://registry.yarnpkg.com/ember-cli-htmlbars/-/ember-cli-htmlbars-5.7.1.tgz#eb5b88c7d9083bc27665fb5447a9b7503b32ce4f"
@@ -9044,19 +9034,16 @@ [email protected]:
     ember-rfc176-data "^0.3.1"
     silent-error "^1.0.1"
 
-ember-cli-showdown@4.5.0:
-  version "4.5.0"
-  resolved "https://registry.yarnpkg.com/ember-cli-showdown/-/ember-cli-showdown-4.5.0.tgz#6ea0d28ced62fd5feb92799bc90d6a4857ceb5a7"
-  integrity sha512-i1XXua2oOqJHGozLw+cXI2zjrfSaamH+qAKt8kLnKTjxDXO175bDUnBtrTR1uMH75S56iIkCBdCSyOMq5haB+g==
+ember-cli-showdown@6.0.1:
+  version "6.0.1"
+  resolved "https://registry.yarnpkg.com/ember-cli-showdown/-/ember-cli-showdown-6.0.1.tgz#ed6407f1bb6911d197bc2257b2c7296c091703b8"
+  integrity sha512-yQJf6ffpnn/5fTiDbwL/zvfzIuRepXzUNpaE9qrI+fo3fhn6KlrbDnr+UqkWYR41DqpspVwV4/sodkyENFu9SQ==
   dependencies:
     broccoli-funnel "^2.0.0"
     broccoli-source "^1.1.0"
     broccoli-string-replace "^0.1.2"
-    ember-cli-babel "^6.8.1"
-    ember-cli-htmlbars "^2.0.3"
-    ember-cli-import-polyfill "^0.2.0"
-    ember-cli-version-checker "^2.1.2"
-    ember-getowner-polyfill "^2.0.1"
+    ember-cli-babel "^7.26.6"
+    ember-cli-htmlbars "^5.7.1"
     resolve "^1.8.1"
     semver "^5.5.0"
     showdown "^1.8.6"
@@ -9404,7 +9391,7 @@ ember-get-config@:
     ember-cli-version-checker "^2.1.0"
     ember-factory-for-polyfill "^1.3.1"
 
-ember-getowner-polyfill@^2.0.0, ember-getowner-polyfill@^2.0.1:
+ember-getowner-polyfill@^2.0.0:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/ember-getowner-polyfill/-/ember-getowner-polyfill-2.0.1.tgz#9bfe2b4d527ed174e76fef2c8f30937d77cb66fb"
   integrity sha1-m/4rTVJ+0XTnb+8sjzCTfXfLZvs=
@@ -16535,11 +16522,6 @@ strip-ansi@^5.0.0, strip-ansi@^5.1.0, strip-ansi@^5.2.0:
   dependencies:
     ansi-regex "^4.1.0"
 
-strip-bom@^3.0.0:
-  version "3.0.0"
-  resolved "https://registry.yarnpkg.com/strip-bom/-/strip-bom-3.0.0.tgz#2334c18e9c759f7bdd56fdef7e9ae3d588e68ed3"
-  integrity sha1-IzTBjpx1n3vdVv3vfprj1YjmjtM=
-
 strip-bom@^4.0.0:
   version "4.0.0"
   resolved "https://registry.yarnpkg.com/strip-bom/-/strip-bom-4.0.0.tgz#9c3505c1db45bcedca3d9cf7a16f5c5aa3901878"