Apply suggestions from code review

Co-authored-by: Doroszlai, Attila <6454655+adoroszlai@users.noreply.github.com>
diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index 6e74267..2597714 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -22,6 +22,6 @@
     runs-on: ubuntu-18.04
     steps:
       - name: checkout source
-        uses: actions/checkout@master
+        uses: actions/checkout@v2
       - name: build image
         run: docker build -t ghcr.io/$(echo $GITHUB_REPOSITORY | sed 's/docker-//g') .
diff --git a/README.md b/README.md
index b66c43c..93d64bc 100644
--- a/README.md
+++ b/README.md
@@ -1,9 +1,8 @@
 # Containerized MIT Kerberos server for Ozone dev environments
 
-This repository containers the container definition of a MIT Kerberos server.
+This repository contains the definition of a containerized MIT Kerberos server.
 
 It's used for development and testing Apache Ozone and **not secured for production use**.
 
 Keytabs required by secure Ozone smoketests are pre-generated which makes possible to export them and store together with the containerized test environments. It makes the tests faster as the keytabs are already exported for each tests.
 
-