add release codename in release pages

Author: kfess

content/en/blog/_posts/2018/kubernetes-1-10-stabilizing-storage-security-networking.md

@@ -6,6 +6,8 @@ slug: kubernetes-1.10-stabilizing-storage-security-networking
 evergreen: true
 release_announcement:
   minor_version: "1.10"
+  themes:
+    - "Left Shark"
 author: >
   [Kubernetes v1.10 Release Team](https://github.com/kubernetes/sig-release/blob/master/releases/release-1.10/release_team.md)
 ---

content/en/blog/_posts/2018/kubernetes-1-11-release-announcement.md

@@ -6,6 +6,8 @@ slug: kubernetes-1.11-release-announcement
 evergreen: true
 release_announcement:
   minor_version: "1.11"
+  themes:
+    - "Eleventy-One: A Long-Expected Release"
 author: >
   [Kubernetes v1.11 Release Team](https://github.com/kubernetes/sig-release/blob/master/releases/release-1.11/release_team.md)
 ---

content/en/blog/_posts/2018/kubernetes-1-12-release-announcement.md

@@ -6,6 +6,8 @@ evergreen: true
 slug: kubernetes-1-12-release-announcement
 release_announcement:
   minor_version: "1.12"
+  themes:
+    - "A next iteration in the evolving stable distributed system"
 author: >
   [Kubernetes v1.12 Release Team](https://github.com/kubernetes/sig-release/blob/master/releases/release-1.12/release_team.md)
 ---

content/en/blog/_posts/2018/kubernetes-1-13-release-announcement.md

@@ -6,6 +6,8 @@ slug: kubernetes-1-13-release-announcement
 evergreen: true
 release_announcement:
   minor_version: "1.13"
+  themes:
+    - "Angel Release"
 author: >
   [Kubernetes v1.13 Release Team](https://github.com/kubernetes/sig-release/blob/master/releases/release-1.13/release_team.md)
 ---

content/en/blog/_posts/2019/1-14-release-announcement.md

@@ -5,6 +5,8 @@ slug: kubernetes-1-14-release-announcement
 evergreen: true
 release_announcement:
   minor_version: "1.14"
+  themes:
+    - "Caturnetes"
 author: >
   [Kubernetes v1.14 Release Team](https://github.com/kubernetes/sig-release/blob/master/releases/release-1.14/release_team.md)
 ---

content/en/blog/_posts/2019/kubernetes-1-15-release-announcement.md

@@ -6,6 +6,8 @@ slug: kubernetes-1-15-release-announcement
 evergreen: true
 release_announcement:
   minor_version: "1.15"
+  themes:
+    - "The Persevering Release"
 author: >
   [Kubernetes 1.15 Release Team](https://github.com/kubernetes/sig-release/blob/master/releases/release-1.15/release_team.md)
 ---

content/en/blog/_posts/2019/kubernetes-1-16-release-announcement.md

@@ -5,6 +5,8 @@ date: 2019-09-18
 slug: kubernetes-1-16-release-announcement
 release_announcement:
   minor_version: "1.16"
+  themes:
+    - "Unlimited Breadsticks For All"
 author: >
   [Kubernetes 1.16 Release Team](https://github.com/kubernetes/sig-release/blob/master/releases/release-1.16/release_team.md)
 ---

content/en/blog/_posts/2019/kubernetes-1.17-release-announcement.md

@@ -6,6 +6,9 @@ slug: kubernetes-1-17-release-announcement
 evergreen: true
 release_announcement:
   minor_version: "1.17"
+  themes:
+    - "Stability"
+    - "The Chillest Release"
 author: >
   [Kubernetes 1.17 Release Team](https://github.com/kubernetes/sig-release/blob/master/releases/release-1.17/release_team.md)
 ---

content/en/blog/_posts/2020/kubernetes-1.18-release-announcement.md

@@ -6,6 +6,9 @@ slug: kubernetes-1-18-release-announcement
 evergreen: true
 release_announcement:
   minor_version: "1.18"
+  themes:
+    - "Fit & Finish"
+    - "A Bit Quarky"
 author: >
   [Kubernetes 1.18 Release Team](https://github.com/kubernetes/sig-release/blob/master/releases/release-1.18/release_team.md) 
 ---

content/en/blog/_posts/2020/kubernetes-release-1.19.md

@@ -6,6 +6,8 @@ slug: kubernetes-release-1.19-accentuate-the-paw-sitive
 evergreen: true
 release_announcement:
   minor_version: "1.19"
+  themes:
+    - "Accentuate the Paw-sitive"
 author: >
   [Kubernetes 1.19 Release Team](https://github.com/kubernetes/sig-release/blob/master/releases/release-1.19/release_team.md)
 ---