Added gpu metrics input plugin to Summary listing for inclusion in website. Fixes #2080.

Signed-off-by: Eric D. Schabell <[email protected]>

Author: eschabell

SUMMARY.md

@@ -96,6 +96,7 @@
   * [Exec WASI](pipeline/inputs/exec-wasi.md)
   * [Fluent Bit metrics](pipeline/inputs/fluentbit-metrics.md)
   * [Forward](pipeline/inputs/forward.md)
+  * [GPU metrics](pipeline/inputs/gpu-metrics.md)
   * [Head](pipeline/inputs/head.md)
   * [Health](pipeline/inputs/health.md)
   * [HTTP](pipeline/inputs/http.md)