docs(fix): host metrics readme snippet

[Eomm]

Which problem is this PR solving?

fixes #1014

Short description of the changes

The readme example is updated to a working snippet

Checklist

• Ran npm run test-all-versions for the edited package(s) on the latest commit if applicable.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: Eomm / name: Manuel Spigolon (b9302ce)

[legendecas]

Thank you for fixing this!

[codecov]

Codecov Report

Merging #1182 (63882a9) into main (e0a2e8e) will increase coverage by 0.30%.
The diff coverage is n/a.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1182      +/-   ##
==========================================
+ Coverage   96.07%   96.37%   +0.30%     
==========================================
  Files          14       20       +6     
  Lines         892     1049     +157     
  Branches      191      201      +10     
==========================================
+ Hits          857     1011     +154     
- Misses         35       38       +3     

Impacted Files	Coverage Δ
packages/opentelemetry-host-metrics/src/metric.ts	100.00% <0.00%> (ø)
...ges/opentelemetry-host-metrics/src/stats/common.ts	100.00% <0.00%> (ø)
...ackages/opentelemetry-host-metrics/src/stats/si.ts	66.66% <0.00%> (ø)
packages/opentelemetry-host-metrics/src/util.ts	91.66% <0.00%> (ø)
packages/opentelemetry-host-metrics/src/enum.ts	100.00% <0.00%> (ø)
...ages/opentelemetry-host-metrics/src/BaseMetrics.ts	100.00% <0.00%> (ø)

[pichlermarc]

This is great! Thanks for updating the docs 🙂