Bump golang in /examples/splunk-hec/logging (open-telemetry#1241)

Bumps golang from 1.17.6-stretch to 1.17.7-stretch.

---
updated-dependencies:
- dependency-name: golang
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

examples/splunk-hec/logging/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.17.6-stretch
+FROM golang:1.17.7-stretch
 
 WORKDIR /go/src/app