multi-arch-test-build: fixup syntax error

Somehow a tab slipped in which is invalid in YAML.

Fixes: c473c7d ("CI: multi-arch-test-build: add telephony feed")
Signed-off-by: Robert Marko <robimarko@gmail.com>

Author: robimarko

.github/workflows/multi-arch-test-build.yml

@@ -89,7 +89,7 @@ jobs:
           if [ "$REPOSITORY_NAME" = "routing" ]; then
             PACKAGES="${PACKAGES:-bird2 cjdns olsrd}"
           elif [ "$REPOSITORY_NAME" = "telephony" ]; then
-	    PACKAGES="${PACKAGES:-asterisk siproxd freeswitch}"
+            PACKAGES="${PACKAGES:-asterisk siproxd freeswitch}"
           else
             PACKAGES="${PACKAGES:-vim attendedsysupgrade-common bmon}"
           fi