build: make Go 1.18 the min version, update to Go 1.19

As usual, we keep with the last two Go versions, which means the last
year of Go release (they release every 6 months or so).

This change means we can now use the type params (generics) in the
project!

docs/release-notes/release-notes-0.16.0.md

@@ -1,5 +1,10 @@
 # Release Notes
 
+## BOLT Specs
+
+* Warning messages from peers are now recognized and
+  [logged](https://github.com/lightningnetwork/lnd/pull/6546) by lnd.
+
 ## RPC
 
 The `RegisterConfirmationsNtfn` call of the `chainnotifier` RPC sub-server [now
@@ -18,9 +23,13 @@ transaction](https://github.com/lightningnetwork/lnd/pull/6730).
 
 * [Add list addresses RPC](https://github.com/lightningnetwork/lnd/pull/6596).
 
+## Build
+
+[The project has updated to Go
+1.19](https://github.com/lightningnetwork/lnd/pull/6795)! Go 1.18 is now the
+minimum version needed to build the project.
+
 ## Misc
-* Warning messages from peers are now recognized and
-  [logged](https://github.com/lightningnetwork/lnd/pull/6546) by lnd.
 
 * [Fixed error typo](https://github.com/lightningnetwork/lnd/pull/6659).