Features
- spanner/spansql: add ROW DELETION POLICY parsing (#4496) (3d6c6c7)
- spanner/spansql: fix unstable SelectFromTable SQL (#4473) (39bc4ec)
- spanner/spansql: support ALTER DATABASE (#4403) (1458dc9)
- spanner/spansql: support table_hint_expr at from_clause on query_statement (#4457) (7047808)
- spanner: add row.String() and refine error message for decoding a struct array (#4431) (f6258a4)
- spanner: allow untyped nil values in parameterized queries (#4482) (c1ba18b)