chore(tazjin/finito): Add build configuration

Adds a Naersk-based build to check that this compiles, with a Lockfile
based on the ~2018 crate versions.

Change-Id: I0460a476d3b983fcf71e35e6b480f4a526118b58
Reviewed-on: https://cl.tvl.fyi/c/depot/+/803
Reviewed-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>
Tested-by: BuildkiteCI

users/tazjin/finito/finito-postgres/src/lib.rs

@@ -113,7 +113,7 @@ pub struct FinitoPostgres<S> {
 }
 
 impl <S> FinitoPostgres<S> {
-    pub fn new(state: S, db_pool: DBPool, pool_size: usize) -> Self {
+    pub fn new(state: S, db_pool: DBPool, _pool_size: usize) -> Self {
         FinitoPostgres {
             state, db_pool,
         }