[chore] fix issuegenerator path (open-telemetry#29318)

workflows have been failing and then trying to use `issuegenerator` to
create issues, but the path for the tool was incorrect. see
https://github.com/open-telemetry/opentelemetry-collector-contrib/actions/runs/6895702499/job/18761957296
as an example

Signed-off-by: Alex Boten <aboten@lightstep.com>

.github/workflows/load-tests.yml

@@ -115,7 +115,7 @@ jobs:
 
       - name: GitHub Issue Generator
         if: ${{ failure() && github.ref == 'refs/heads/main' }}
-        run: issuegenerator $TEST_RESULTS
+        run: ./.tools/issuegenerator $TEST_RESULTS
 
   update-benchmarks:
     runs-on: ubuntu-latest