Fix docker build

Signed-off-by: Norman Ziegner <norman.ziegner@ufz.de>

.gitlab-ci-gfz.yml

@@ -69,7 +69,9 @@ test-frontend-unit-tests:
 
 build-deploy-image:
   stage: build
-  image: docker:19.03.1
+  image: docker:20.10.7
+  services:
+    - docker:20.10.7-dind
   variables:
     SMS_BACKEND_URL: ${STAGING_BACKEND_URL}/rdm/svm-api/v1
     CV_BACKEND_URL: ${STAGING_SMS_CV_BACKEND_URL}/api/v1
@@ -115,7 +117,9 @@ build-deploy-image:
 
 build-deploy-image-manual:
   stage: build
-  image: docker:19.03.1
+  image: docker:20.10.7
+  services:
+    - docker:20.10.7-dind
   variables:
     SMS_BACKEND_URL: ${STAGING_BACKEND_URL}/rdm/svm-api/v1
     CV_BACKEND_URL: ${STAGING_SMS_CV_BACKEND_URL}/api/v1