internal/lsp: switch to 'go get -u ./...' for transitive upgrades
internal/lsp: switch to 'go get -u ./...' for transitive upgrades

'go get -u all' works for this in Go 1.16, but in earlier versions,
we need 'go get -u ./...'. Also, include the -d and -t flags to avoid
building binaries and to upgrade test dependencies.

Fixes golang/go#45262

Change-Id: I8b04783ffcd53e8066c5a25fef72d91ae975f5a2
Reviewed-on: https://go-review.googlesource.com/c/tools/+/307889
Trust: Rebecca Stambler <d7cf11e5f299d88ea8348366a9fc4f7c335c3afa@golang.org>
Run-TryBot: Rebecca Stambler <d7cf11e5f299d88ea8348366a9fc4f7c335c3afa@golang.org>
gopls-CI: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
TryBot-Result: Go Bot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Heschi Kreinick <e89ab2b172855aa0ad01c40c4d8a3535a61ac68a@google.com>

golang/tools,golang/tools,golang/tools,golang/tools,golang/tools