[fix][fn] fix broken function-go test

[pgier]

Upgrade the prometheus client_golang library which changes the format of the metric output to match the current tests.

Motivation

A previous upgrade (#20579) to the prometheus client library broke one of the tests because the spacing changes in the serialized metric output. The specifc commit in prometheus that caused this change is here: prometheus/client_golang#955

Version v1.15.1 of the prometheus client lib changes the spacing back to what it was in v1.11.0. However, it seems that this spacing is not consistent between versions, so we may want to make the test more flexible in the future to avoid hitting this issue again in future upgrades.

=== RUN   TestExampleSummaryVec
    stats_test.go:149:
        	Error Trace:	/Users/paulgier/projects/apache/pulsar/pulsar-function-go/pf/stats_test.go:149
        	Error:      	Not equal:
        	            	expected: "name: \"pond_temperature_celsius\"\nhelp: \"The temperature of the frog pond.\"\ntype: SUMMARY\nmetric: {\n  label: {\n    name: \"species\"\n    value: \"leiopelma-hochstetteri\"\n  }\n  summary: {\n    sample_count: 0\n    sample_sum: 0\n    quantile: {\n      quantile: 0.5\n      value: nan\n    }\n    quantile: {\n      quantile: 0.9\n      value: nan\n    }\n    quantile: {\n      quantile: 0.99\n      value: nan\n    }\n  }\n}\nmetric: {\n  label: {\n    name: \"species\"\n    value: \"lithobates-catesbeianus\"\n  }\n  summary: {\n    sample_count: 1000\n    sample_sum: 31956.100000000017\n    quantile: {\n      quantile: 0.5\n      value: 32.4\n    }\n    quantile: {\n      quantile: 0.9\n      value: 41.4\n    }\n    quantile: {\n      quantile: 0.99\n      value: 41.9\n    }\n  }\n}\nmetric: {\n  label: {\n    name: \"species\"\n    value: \"litoria-caerulea\"\n  }\n  summary: {\n    sample_count: 1000\n    sample_sum: 29969.50000000001\n    quantile: {\n      quantile: 0.5\n      value: 31.1\n    }\n    quantile: {\n      quantile: 0.9\n      value: 41.3\n    }\n    quantile: {\n      quantile: 0.99\n      value: 41.9\n    }\n  }\n}\n"
        	            	actual  : "name:  \"pond_temperature_celsius\"\nhelp:  \"The temperature of the frog pond.\"\ntype:  SUMMARY\nmetric:  {\n  label:  {\n    name:  \"species\"\n    value:  \"leiopelma-hochstetteri\"\n  }\n  summary:  {\n    sample_count:  0\n    sample_sum:  0\n    quantile:  {\n      quantile:  0.5\n      value:  nan\n    }\n    quantile:  {\n      quantile:  0.9\n      value:  nan\n    }\n    quantile:  {\n      quantile:  0.99\n      value:  nan\n    }\n  }\n}\nmetric:  {\n  label:  {\n    name:  \"species\"\n    value:  \"lithobates-catesbeianus\"\n  }\n  summary:  {\n    sample_count:  1000\n    sample_sum:  31956.100000000017\n    quantile:  {\n      quantile:  0.5\n      value:  32.4\n    }\n    quantile:  {\n      quantile:  0.9\n      value:  41.4\n    }\n    quantile:  {\n      quantile:  0.99\n      value:  41.9\n    }\n  }\n}\nmetric:  {\n  label:  {\n    name:  \"species\"\n    value:  \"litoria-caerulea\"\n  }\n  summary:  {\n    sample_count:  1000\n    sample_sum:  29969.50000000001\n    quantile:  {\n      quantile:  0.5\n      value:  31.1\n    }\n    quantile:  {\n      quantile:  0.9\n      value:  41.3\n    }\n    quantile:  {\n      quantile:  0.99\n      value:  41.9\n    }\n  }\n}\n"

Modifications

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• [ X ] The metrics
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Matching PR in forked repository

PR in forked repository: pgier#12

[lhotari]

LGTM. Thanks for the contribution @pgier

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 73.61%. Comparing base (bbc6224) to head (9c5cf0f).
Report is 1136 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #22260      +/-   ##
============================================
+ Coverage     73.57%   73.61%   +0.03%     
- Complexity    32624    32755     +131     
============================================
  Files          1877     1879       +2     
  Lines        139502   139794     +292     
  Branches      15299    15340      +41     
============================================
+ Hits         102638   102906     +268     
- Misses        28908    28909       +1     
- Partials       7956     7979      +23     

Flag	Coverage Δ
inttests	26.48% <ø> (+1.90%)	⬆️
systests	24.39% <ø> (+0.06%)	⬆️
unittests	72.87% <ø> (+0.02%)	⬆️

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see 83 files with indirect coverage changes

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