Update pg_query_go to v2.1.2

Relevant changes that apply to the collector:

- Fixes memory leak in pg_query_fingerprint error handling [#141](pganalyze/libpg_query#141)
- Add support for parsing more operators that include a `?` character (special cased to support old pg_stat_statements query texts)
  - ltree extension [#136](pganalyze/libpg_query#136)
  - promscale extension [#133](pganalyze/libpg_query#133)

go.mod

@@ -36,7 +36,7 @@ require (
  github.com/mitchellh/mapstructure v1.4.2 // indirect
  github.com/ogier/pflag v0.0.0-20160129220114-45c278ab3607
  github.com/papertrail/go-tail v0.0.0-20180509224916-973c153b0431
- github.com/pganalyze/pg_query_go/v2 v2.1.0
+ github.com/pganalyze/pg_query_go/v2 v2.1.2
  github.com/pkg/errors v0.9.1
  github.com/satori/go.uuid v0.0.0-20160713180306-0aa62d5ddceb
  github.com/shirou/gopsutil v3.21.10+incompatible

go.sum

@@ -255,8 +255,8 @@ github.com/ogier/pflag v0.0.0-20160129220114-45c278ab3607 h1:db+rES1EpSjP45xOU3h
 github.com/ogier/pflag v0.0.0-20160129220114-45c278ab3607/go.mod h1:zkFki7tvTa0tafRvTBIZTvzYyAu6kQhPZFnshFFPE+g=
 github.com/papertrail/go-tail v0.0.0-20180509224916-973c153b0431 h1:i1egM7gz4bPxLCIwBJOkpk6TqHpjTnL4dE1xdN/4dcs=
 github.com/papertrail/go-tail v0.0.0-20180509224916-973c153b0431/go.mod h1:dMID0RaS2a5rhpOjC4RsAKitU6WGgkFBZnPVffL69b8=
-github.com/pganalyze/pg_query_go/v2 v2.1.0 h1:donwPZ4G/X+kMs7j5eYtKjdziqyOLVp3pkUrzb9lDl8=
-github.com/pganalyze/pg_query_go/v2 v2.1.0/go.mod h1:XAxmVqz1tEGqizcQ3YSdN90vCOHBWjJi8URL1er5+cA=
+github.com/pganalyze/pg_query_go/v2 v2.1.2 h1:LiNm3WoBV/cc144X6jlVKD5DPL+fI2wfvCXT7z25B8U=
+github.com/pganalyze/pg_query_go/v2 v2.1.2/go.mod h1:XAxmVqz1tEGqizcQ3YSdN90vCOHBWjJi8URL1er5+cA=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=