fix(attic): remove variable that was redundant and referenced the wrong value

charts/attic/templates/deployment-server.yaml

@@ -20,9 +20,6 @@ spec:
         image: {{ .Values.image.repository }}:{{ .Values.image.tag }}
         command: ["atticd"]
         args: ["-f", "/var/lib/atticd/config.toml"]
-        env:
-          - name: ATTIC_SERVER_TOKEN_HS256_SECRET_BASE64
-            value: {{ .Values.config.externalUrl }}
         envFrom:
           - secretRef:
               name: {{ .Values.envFromSecret }}