Fix Helm chart version bump script

Instead of relying on semver which is not installed, just parse it with
bash.

ci/build/update-repo.sh

@@ -2,16 +2,65 @@
 
 set -Eeuo pipefail
 
-function update_helm() {
-  local current
-  current=$(yq .version ci/helm-chart/Chart.yaml)
-  local next
-  next=$(semver "$current" -i minor)
-  echo "Bumping version from $current to $next..."
-  sed -i.bak "s/^version: $current\$/version: $next/" ci/helm-chart/Chart.yaml
+# Given versions $1 and $2 figure out the first component that is different
+# (major, minor, patch).
+function find_version_diff() {
+  # shellcheck disable=SC2206
+  local a=( ${1//./ } )
+  # shellcheck disable=SC2206
+  local b=( ${2//./ } )
 
-  echo "Setting app version and image to $version..."
+  if [[ ${a[0]} != "${b[0]}" ]] ; then
+    echo major
+  elif [[ ${a[1]} != "${b[1]}" ]] ; then
+    echo minor
+  else
+    echo patch
+  fi
+}
+
+# Bump $1 by the bump type (major, minor, patch) in $2.
+function bump_version() {
+  # shellcheck disable=SC2206
+  local a=( ${1//./ } )
+  case $2 in
+    major)
+      ((a[0]++))
+      a[1]=0
+      a[2]=0
+      ;;
+    minor)
+      ((a[1]++))
+      a[2]=0
+      ;;
+    *)
+      ((a[2]++))
+      ;;
+  esac
+  echo "${a[0]}.${a[1]}.${a[2]}"
+}
+
+function update_helm() {
+  local chart_version
+  chart_version=$(yq .version ci/helm-chart/Chart.yaml)
+  local app_version
+  app_version=$(yq .appVersion ci/helm-chart/Chart.yaml)
+  local image_version
+  image_version=$(yq .image.tag ci/helm-chart/values.yaml)
+
+  local bump_type
+  bump_type=$(find_version_diff "$app_version" "$version")
+  local chart_version_bump
+  chart_version_bump=$(bump_version "$chart_version" "$bump_type")
+
+  # Use sed to replace because yq will reformat.
+  echo "Bumping version from $chart_version to $chart_version_bump..."
+  sed -i.bak "s/^version: $chart_version\$/version: $chart_version_bump/" ci/helm-chart/Chart.yaml
+
+  echo "Bumping app version from $app_version to $version..."
   sed -i.bak "s/^appVersion: .\+\$/appVersion: $version/" ci/helm-chart/Chart.yaml
+
+  echo "Bumping image version from $image_version to $version..."
   sed -i.bak "s/^  tag: .\+\$/  tag: '$version'/" ci/helm-chart/values.yaml
 }