chore(imports): improve import paths

src/ContentContainer.vue

@@ -17,7 +17,7 @@
 </template>
 
 <script>
-import useContentContainer from './useContentContainer';
+import useContentContainer from './useContentContainer.js';
 
 export default {
   inheritAttrs: false,

src/ContentHeadline.vue

@@ -6,7 +6,7 @@
 </template>
 
 <script>
-import useContentHeadline from './useContentHeadline';
+import useContentHeadline from './useContentHeadline.js';
 
 export default {
   inheritAttrs: false,

src/index.js

@@ -1,4 +1,4 @@
 export { default as ContentContainer } from './ContentContainer.vue';
 export { default as ContentHeadline } from './ContentHeadline.vue';
-export { default as useContentContainer } from './useContentContainer';
-export { default as useContentHeadline } from './useContentHeadline';
+export { default as useContentContainer } from './useContentContainer.js';
+export { default as useContentHeadline } from './useContentHeadline.js';