Update ghcr.io/element-hq/element-call Docker tag to v0.21.0

roles/custom/matrix-element-call/defaults/main.yml

@@ -21,7 +21,7 @@ matrix_element_call_enabled: false
 matrix_rtc_enabled: "{{ matrix_element_call_enabled }}"
 
 # renovate: datasource=docker depName=ghcr.io/element-hq/element-call
-matrix_element_call_version: v0.20.3
+matrix_element_call_version: v0.21.0
 
 matrix_element_call_scheme: https