fix: correct schema upgrade logic (and refactor)

Schema upgrades were buggy from 4->5 (the v5 would be skipped).  This
change also refactors the logic slightly so that future additions can
be clearer (no need to have if and else-if combinations).

Cargo.lock

@@ -286,6 +286,26 @@ dependencies = [
  "tracing-subscriber 0.3.15",
 ]
 
+[[package]]
+name = "const_format"
+version = "0.2.28"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "79f926bc2341a80e6bb5a16e18057c8c90ca3edbdeb9fa497bd0f82b1f4df4e6"
+dependencies = [
+ "const_format_proc_macros",
+]
+
+[[package]]
+name = "const_format_proc_macros"
+version = "0.2.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ef196d5d972878a48da7decb7686eded338b4858fbabeed513d63a7c98b2b82d"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-xid",
+]
+
 [[package]]
 name = "core-foundation"
 version = "0.9.3"
@@ -1008,6 +1028,7 @@ dependencies = [
  "bitcoin_hashes",
  "config",
  "console-subscriber",
+ "const_format",
  "futures",
  "futures-util",
  "governor",
@@ -2216,6 +2237,12 @@ dependencies = [
  "tinyvec",
 ]
 
+[[package]]
+name = "unicode-xid"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f962df74c8c05a667b5ee8bcf162993134c104e96440b663c8daa176dc772d8c"
+
 [[package]]
 name = "url"
 version = "2.3.1"