Fix regression on plugin installation for Helm 2

Fixes #223

Author: mumoshu

install-binary.sh

@@ -8,9 +8,7 @@ export GREP_COLOR="never"
 
 HELM_MAJOR_VERSION=$(helm version --client --short | awk -F '.' '{print $1}')
 
-if [ "$HELM_MAJOR_VERSION" = "Client: v2" ]; then
-  : ${HELM_PLUGIN_DIR:="$(helm home --debug=false)/plugins/helm-diff"}
-fi
+: ${HELM_PLUGIN_DIR:="$(helm home --debug=false)/plugins/helm-diff"}
 
 # Convert the HELM_PLUGIN_DIR to unix if cygpath is
 # available. This is the case when using MSYS2 or Cygwin

scripts/dep-helm-version.sh

@@ -0,0 +1,3 @@
+#/bin/sh
+
+grep "k8s.io/helm" go.mod | sed -n -e "s/.*k8s.io\/helm \(v[.0-9]*\).*/\1/p"