Restrict runner ENV access

Author: DavidGOrtega

src/drivers/github.js

@@ -265,7 +265,8 @@ class Github {
       );
 
       return spawn(resolve(workdir, 'run.sh'), {
-        shell: true
+        shell: true,
+        env: {}
       });
     } catch (err) {
       throw new Error(`Failed preparing GitHub runner: ${err.message}`);

src/drivers/gitlab.js

@@ -204,7 +204,7 @@ class Gitlab {
         --docker-runtime "${gpu ? 'nvidia' : ''}" \
         ${single ? '--max-builds 1' : ''}`;
 
-      return spawn(command, { shell: true });
+      return spawn(command, { shell: true, env: {} });
     } catch (err) {
       throw new Error(`Failed preparing Gitlab runner: ${err.message}`);
     }