Don't use --locked for mdbook-svgbob.

This should build it with a newer version of mdbook, to support Rust\
2024 edition.

Author: qwandor

install-mdbook.sh

@@ -2,7 +2,7 @@
 # The --locked flag is important for reproducible builds. It also
 # avoids breakage due to skews between mdbook and mdbook-svgbob.
 cargo install mdbook --locked --version 0.4.44
-cargo install mdbook-svgbob --locked --version 0.2.1
+cargo install mdbook-svgbob --version 0.2.1
 cargo install mdbook-pandoc --locked --version 0.9.3
 cargo install mdbook-i18n-helpers --locked --version 0.3.6
 cargo install i18n-report --locked --version 0.2.0