feat(module:steps): support [nzProgressDot] property in vertical mode (#446)

Author: hsuanxyz

src/components/steps/style/patch.less

@@ -1,7 +1,29 @@
+@import "../../style/themes/default";
+
+@steps-prefix-cls: ~"@{ant-prefix}-steps";
+
 .ant-steps-horizontal nz-step:not(:first-child) .ant-steps-head{
   padding-left: 10px;
   margin-left: -10px;
 }
 nz-step{
   display: block;
 }
+
+.@{steps-prefix-cls}-dot {
+  &.@{steps-prefix-cls}-vertical {
+    .@{steps-prefix-cls}-tail {
+      margin-left: 0;
+    }
+    .@{steps-prefix-cls}-step {
+      text-align: left;
+      width: auto;
+    }
+    .@{steps-prefix-cls}-head-inner {
+      margin-right: 16px;
+    }
+    .@{steps-prefix-cls}-main {
+      margin-top: 0;
+    }
+  }
+}