chore: increase machine size and change pkg-config

I've been troubleshooting this via a SSH session but the build process
OOMs when I try and pass logs through `tee` so bumping the resource class up

Also replacing the influx pkg-config with my modified one.

Testing in instance *seems* to have reduced the failures down to one path
but need to re-run from clean to confirm

.circleci/config.yml

@@ -97,7 +97,7 @@ jobs:
   build-windows:
     machine:
       image: windows-server-2019-vs2019:stable
-    resource_class: windows.medium
+    resource_class: windows.large
     shell: bash.exe -eo pipefail
     steps:
       - run:
@@ -146,7 +146,7 @@ jobs:
             echo "export GOPATH='${GOPATH}'" >> $BASH_ENV
             mkdir -p "${GOPATH}/bin"
             echo 'export PATH="${GOPATH}/bin:${PATH}"' >> $BASH_ENV
-            go install github.com/influxdata/pkg-config
+            go install github.com/btasker/pkg-config
       - run:
           name: Generate libflux
           command: go generate ./libflux/go/libflux

go.mod

@@ -31,7 +31,7 @@ require (
 	github.com/influxdata/influxdb-client-go/v2 v2.3.1-0.20210518120617-5d1fff431040
 	github.com/influxdata/line-protocol v0.0.0-20200327222509-2487e7298839
 	github.com/influxdata/line-protocol/v2 v2.2.1
-	github.com/influxdata/pkg-config v0.2.11
+	github.com/btasker/pkg-config v0.0.3
 	github.com/influxdata/tdigest v0.0.2-0.20210216194612-fc98d27c9e8b
 	github.com/lib/pq v1.0.0
 	github.com/mattn/go-runewidth v0.0.3 // indirect