gopls/internal/lsp/mod: deleted unused function pkgVersion
gopls/internal/lsp/mod: deleted unused function pkgVersion

Change-Id: I85cabd92a1ee28f60ad355c4f44577e0ccc0bd07
Reviewed-on: https://go-review.googlesource.com/c/tools/+/448977
gopls-CI: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
TryBot-Result: Gopher Robot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Peter Weinberger <dd140fb9530d791057dd8833ea6768ff65fcde71@google.com>
Run-TryBot: Hyang-Ah Hana Kim <d7e82c3c07f92613bcbf9a1e88f6b96c13caa3b0@gmail.com>

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