astro 0.21.11

#2137 cc1dae55 Thanks @natemoo-re! - Exclude 404 pages from sitemap generation
#2112 da7b41f5 Thanks @drwpow! - Bugfix: fix missing styles in build
#2116 d9d3906a Thanks @e111077! - add lit renderer reflection tests
#2135 77c3fda3 Thanks @natemoo-re! - Patch fetch support to prioritize authored code. Existing fetch imports and declarations are respected.