DEVOPS-7210: Update Helm to 3.7 version (#27)

* Update Helm to 3.7.2 and helmfile to 0.144 version.
* Update Helm diff plugin to 3.5.0 version.

Dockerfile

@@ -1,11 +1,11 @@
 FROM alpine:3.9.3
 
 ENV HELM_VERSION v2.17.0
-ENV HELM_DIFF_VERSION v3.1.3
+ENV HELM_DIFF_VERSION v3.5.0
 ENV HELM_SECRET_VERSION v1.3.1
-ENV HELM_V3_VERSION v3.1.3
-ENV HELM_V3_SHA256 7ca15cb5e3a76393eccd7389f2b3d20082b8c535b6689882613bfcc4a7d07c23 
-ENV HELMFILE_VERSION 0.142.0
+ENV HELM_V3_VERSION v3.7.2
+ENV HELM_V3_SHA256 4ae30e48966aba5f807a4e140dad6736ee1a392940101e4d79ffb4ee86200a9e 
+ENV HELMFILE_VERSION 0.144.0
 ENV AWS_IAM_AUTH_VERSION 0.4.0
 ENV VAULT_VERSION 1.3.1
 ENV AWS_CLI_VERSION 1.16.276