Bump SQLx to 0.8 #681

Job	Run time
Compile Postgres (live/postgres)	3m 19s
Compile MySQL (live/mysql)	3m 21s
Compile SQLite (live/sqlite)	3m 15s
Compile Postgres (discovery/postgres)	3m 17s
Compile MySQL (discovery/mysql)	3m 21s
Compile SQLite (discovery/sqlite)	3m 8s
Clippy	1m 10s
Compile Postgres (writer/postgres)	3m 21s
Compile MySQL (writer/mysql)	3m 18s
Compile SQLite (writer/sqlite)	3m 7s
Rustfmt	12s
Unit Test	1m 23s
SQLite (live/sqlite)	31s
SQLite (discovery/sqlite)	18s
SQLite (writer/sqlite)	24s
Postgres (14.4, live/postgres)	1m 3s
Postgres (14.4, discovery/postgres)	1m 2s
Postgres (14.4, writer/postgres)	1m 21s
MariaDB (10.6, live/mysql)	44s
MySQL (8, live/mysql)	51s
MariaDB (10.6, discovery/mysql)	41s
MySQL (8, discovery/mysql)	48s
MariaDB (10.6, writer/mysql)	45s
MySQL (8, writer/mysql)	47s
MySQL (5.7, live/mysql)	57s
MySQL (5.7, discovery/mysql)	46s
MySQL (5.7, writer/mysql)	58s
	44m 8s

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