Update rusqlite to 0.27

The release is >1yo but they keep breaking the MSRV so we can't get the
fixes without upgrading to a bleeding edge compiler...

This upgrades the bundled SQLite to version 3.38, which had quite some
patch releases but no issue that should be relevant to us.
https://sqlite.org/releaselog/3_38_0.html

Full rusqlite changelog available here:
https://github.com/rusqlite/rusqlite/releases/tag/v0.27.0.

Cargo.lock

@@ -243,9 +243,9 @@ checksum = "99227334921fae1a979cf0bfdfcc6b3e5ce376ef57e16fb6fb3ea2ed6095f80c"
 
 [[package]]
 name = "libsqlite3-sys"
-version = "0.23.0"
+version = "0.24.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c4ecc4273169aeb654a26ba8c7e087947caad92c9d121886eafa6446d4ebe138"
+checksum = "898745e570c7d0453cc1fbc4a701eb6c662ed54e8fec8b7d14be137ebeeb9d14"
 dependencies = [
  "cc",
  "pkg-config",
@@ -364,9 +364,9 @@ dependencies = [
 
 [[package]]
 name = "rusqlite"
-version = "0.26.3"
+version = "0.27.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4ba4d3462c8b2e4d7f4fcfcf2b296dc6b65404fbbc7b63daa37fd485c149daf7"
+checksum = "85127183a999f7db96d1a976a309eebbfb6ea3b0b400ddd8340190129de6eb7a"
 dependencies = [
  "bitflags",
  "fallible-iterator",

Cargo.toml

@@ -44,9 +44,9 @@ fern = "0.6"
 # to work with our custom panic hook.
 backtrace = "0.3"
 
-# Pinned to this version because they broke the MSRV in 0.27...
+# Pinned to this version because they keep breaking their MSRV in point releases...
 # FIXME: this is unfortunate, we don't receive the updates (sometimes critical) from SQLite.
-rusqlite = { version = "0.26.3", features = ["bundled", "unlock_notify"] }
+rusqlite = { version = "0.27", features = ["bundled", "unlock_notify"] }
 
 # To talk to bitcoind
 jsonrpc = "0.12"