Update pq to resolve concurrent map issue

[hannahhoward]

Goals

We're getting crashes on the Dealbot due to a concurrent map write that appears in the PQ code.

Fortunately, it appears a fix was deployed in an update to pq

Implementation

Update PQ.

For Discussion

Our stack trace:

goroutine 3340 [running]:
runtime.throw(0x3bf7250, 0x15)
	/usr/local/go/src/runtime/panic.go:1117 +0x72 fp=0xc001043cf8 sp=0xc001043cc8 pc=0x1166332
runtime.mapdelete_faststr(0x37fb940, 0xc0005e3ec0, 0x3bd9717, 0x9)
	/usr/local/go/src/runtime/map_faststr.go:306 +0x3de fp=0xc001043d60 sp=0xc001043cf8 pc=0x1142a9e
github.com/lib/pq.ssl(0xc0005e3ec0, 0x10, 0xc000902cc0, 0x7fa0746eb218)
	/go/pkg/mod/github.com/lib/pq@v1.10.0/ssl.go:63 +0x178 fp=0xc001043dd0 sp=0xc001043d60 pc=0x1d42e18
github.com/lib/pq.(*conn).ssl(0xc000c96b00, 0xc0005e3ec0, 0x550e740, 0xc001058de0)

original PQ issue: lib/pq#1031

Fix PR in dep: lib/pq#1035

[coryschwartz]

Amazing. Thanks for find this.