Make Postgres 17 the default version (#11619)

This is mostly a documentation update, but a few updates with regard to
neon_local, pageserver, and tests.

17 is our default for users in production, so dropping references to 16
makes sense.

Signed-off-by: Tristan Partin <tristan@neon.tech>

Signed-off-by: Tristan Partin <tristan@neon.tech>

pageserver/src/lib.rs

@@ -49,7 +49,7 @@ use tracing::{info, info_span};
 /// backwards-compatible changes to the metadata format.
 pub const STORAGE_FORMAT_VERSION: u16 = 3;
 
-pub const DEFAULT_PG_VERSION: u32 = 16;
+pub const DEFAULT_PG_VERSION: u32 = 17;
 
 // Magic constants used to identify different kinds of files
 pub const IMAGE_FILE_MAGIC: u16 = 0x5A60;

pageserver/src/tenant/metadata.rs

@@ -564,8 +564,9 @@ mod tests {
             Lsn(0),
             Lsn(0),
             Lsn(0),
-            // Any version will do here, so use the default
-            crate::DEFAULT_PG_VERSION,
+            // Updating this version to 17 will cause the test to fail at the
+            // next assert_eq!().
+            16,
         );
         let expected_bytes = vec![
             /* TimelineMetadataHeader */