api: Specify ruby bundler for api gen

This patch updates the Dockerfile used to generate API bindings to
specify an explicit version of the Ruby bundler program. This is
required since an older version of Ruby is used as the newer ones
are not compatible with the API generation code.

Signed-off-by: akutz <andrew.kutz@broadcom.com>

Author: akutz

gen/Dockerfile

@@ -55,8 +55,9 @@ ENV PATH="/root/.rbenv/shims:${PATH}" \
 RUN apt-get install -y rbenv && \
     rbenv install 2.7.6 && \
     rbenv rehash && \
-    rbenv global 2.7.6 && \
-    gem install bundler
+    rbenv global 2.7.6
+
+RUN gem install bundler -v 2.4.22
 
 
 ## --------------------------------------
@@ -71,6 +72,11 @@ WORKDIR /govmomi/gen
 ## --------------------------------------
 
 COPY Gemfile Gemfile.lock .
-RUN go install golang.org/x/tools/cmd/goimports@latest && \
-    bundle update --bundler && \
-    bundle install
+RUN bundle update --bundler && bundle install
+
+
+## --------------------------------------
+## Install goimports to forma gen'd files
+## --------------------------------------
+
+RUN go install golang.org/x/tools/cmd/goimports@latest