Allow configuration of Pod Labels (#131)

Allow the configuration of additional Pod Labels. There are several use cases for this, one of which is injecting Istio sidecars which can only be done via Pod Labels.
diff --git a/couchdb/Chart.yaml b/couchdb/Chart.yaml
index f5e44cf..e04d936 100644
--- a/couchdb/Chart.yaml
+++ b/couchdb/Chart.yaml
@@ -1,6 +1,6 @@
 apiVersion: v1
 name: couchdb
-version: 4.4.4
+version: 4.4.5
 appVersion: 3.3.2
 description: A database featuring seamless multi-master sync, that scales from
   big data to mobile, with an intuitive HTTP/JSON API and designed for
diff --git a/couchdb/README.md b/couchdb/README.md
index 7c76bf8..a0b8690 100644
--- a/couchdb/README.md
+++ b/couchdb/README.md
@@ -200,6 +200,7 @@
 | `podManagementPolicy`                | Parallel                                         |
 | `affinity`                           |                                                  |
 | `topologySpreadConstraints`          |                                                  |
+| `labels`                             |                                                  |
 | `annotations`                        |                                                  |
 | `tolerations`                        |                                                  |
 | `resources`                          |                                                  |
diff --git a/couchdb/README.md.gotmpl b/couchdb/README.md.gotmpl
index 261d081..b8de044 100644
--- a/couchdb/README.md.gotmpl
+++ b/couchdb/README.md.gotmpl
@@ -185,6 +185,7 @@
 | `podManagementPolicy`                | Parallel                                                                                                                                                     |
 | `affinity`                           |                                                                                                                                                              |
 | `topologySpreadConstraints`          |                                                                                                                                                              |
+| `labels`                             |                                                                                                                                                              |
 | `annotations`                        |                                                                                                                                                              |
 | `tolerations`                        |                                                                                                                                                              |
 | `resources`                          |                                                                                                                                                              |
diff --git a/couchdb/templates/statefulset.yaml b/couchdb/templates/statefulset.yaml
index 9104879..f5c93bd 100644
--- a/couchdb/templates/statefulset.yaml
+++ b/couchdb/templates/statefulset.yaml
@@ -18,6 +18,9 @@
     metadata:
       labels:
 {{ include "couchdb.ss.selector" . | indent 8 }}
+{{- if .Values.labels }}
+{{ toYaml .Values.labels | indent 8 }}
+{{- end }}
       annotations:
         checksum/config: {{ include (print $.Template.BasePath "/configmap.yaml") . | sha256sum }}
         checksum/secret: {{ include (print $.Template.BasePath "/secrets.yaml") . | sha256sum }}
@@ -35,7 +38,7 @@
         - name: init-copy
           image: "{{ .Values.initImage.repository }}:{{ .Values.initImage.tag }}"
           imagePullPolicy: {{ .Values.initImage.pullPolicy }}
-          command: 
+          command:
             - 'sh'
             - '-c'
 {{- if .Values.prometheusPort.enabled }}
@@ -199,7 +202,7 @@
               - key: seedlistinifile
                 path: seedlist.ini
 {{- if .Values.prometheusPort.enabled }}
-              - key: prometheusinifile 
+              - key: prometheusinifile
                 path: prometheus.ini
 {{- end }}
 
diff --git a/couchdb/values.yaml b/couchdb/values.yaml
index 266ce11..35d3e67 100644
--- a/couchdb/values.yaml
+++ b/couchdb/values.yaml
@@ -124,6 +124,9 @@
   #       matchLabels:
   #         app: couchdb
 
+## Optional pod labels
+labels: {}
+
 ## Optional pod annotations
 annotations: {}