Fix CI additional step

Author: etan-status

.github/workflows/ci.yml

@@ -248,7 +248,9 @@ jobs:
           done
 
       - name: Build with custom SECONDS_PER_SLOT
-        run: nim c --passC:-fsyntax-only --noLinking:on -d:chronicles_log_level=TRACE -d:SECONDS_PER_SLOT=1 beacon_chain/nimbus_beacon_node
+        run: |
+          source env.sh
+          nim c --passC:-fsyntax-only --noLinking:on -d:chronicles_log_level=TRACE -d:SECONDS_PER_SLOT=1 beacon_chain/nimbus_beacon_node
 
   lint:
     name: "Lint"