Pgvector

- Improved cost estimation
- Improved support for spaces with text input
- Fixed infinite and NaN values with binary input
- Fixed infinite values with vector addition and subtraction
- Fixed infinite values with list centers
- Fixed compilation error when `float8` is pass by reference
- Fixed compilation error on PowerPC
- Fixed segmentation fault with index creation on i386

- Added notice when index created with little data
- Fixed dimensions check for some direct function calls
- Fixed installation error with Postgres 12.0-12.2

- Improved performance of cosine distance
- Fixed index scan count

If upgrading with Postgres < 13, see [this note](https://github.com/pgvector/pgvector/blob/v0.4.0/README.md#040).

- Changed text representation for vector elements to match `real`
- Changed storage for vector from `plain` to `extended`
- Increased max dimensions for vector from 1024 to 16000
- Increased max dimensions for index from 1024 to 2000
- Improved accuracy of text parsing for certain inputs
- Added `avg` aggregate for vector
- Added experimental support for Windows
- Dropped support for Postgres 10

- Added `arrays` option for Psycopg 2

- Added `avg` function with type casting to SQLAlchemy
- Added `globally` option for Psycopg 2