Replace prepend-left-64 css class

This replaces the prepend-left-64
utility class and replaces it for the
gl-ml-11 utility class from GitLab-UI

app/assets/javascripts/pipelines/components/graph/graph_component.vue

@@ -170,7 +170,7 @@ export default {
             v-for="(stage, index) in graph"
             :key="stage.name"
             :class="{
-              'has-upstream prepend-left-64': hasUpstream(index),
+              'has-upstream gl-ml-11': hasUpstream(index),
               'has-only-one-job': hasOnlyOneJob(stage),
               'gl-mr-26': shouldAddRightMargin(index),
             }"

app/assets/javascripts/pipelines/components/graph/linked_pipelines_column.vue

@@ -27,7 +27,7 @@ export default {
   computed: {
     columnClass() {
       const positionValues = {
-        right: 'prepend-left-64',
+        right: 'gl-ml-11',
         left: 'gl-mr-7',
       };
       return `graph-position-${this.graphPosition} ${positionValues[this.graphPosition]}`;

app/assets/stylesheets/framework/common.scss

@@ -401,7 +401,6 @@ img.emoji {
 .prepend-top-20 { margin-top: 20px; }
 .prepend-left-15 { margin-left: 15px; }
 .prepend-left-20 { margin-left: 20px; }
-.prepend-left-64 { margin-left: 64px; }
 .append-right-20 { margin-right: 20px; }
 .append-bottom-20 { margin-bottom: 20px; }
 .ml-10 { margin-left: 4.5rem; }