fix: update meson options to avoid deprecation warnings

- Remove quotes from boolean values in meson_options.txt
- see https://mesonbuild.com/Release-notes-for-1-1-0.html#coercing-values-in-the-option-function-is-deprecated

Author: Dominik Loidolt

meson_options.txt

@@ -1,3 +1,3 @@
-option('extension_fixture', type: 'boolean', value: 'false', description: 'Whether to enable the fixture extension.')
-option('extension_memory', type: 'boolean', value: 'false', description: 'Whether to enable the memory extension.')
-option('support_double', type: 'boolean', value: 'false', description: 'Whether to enable double precision floating point assertions.')
+option('extension_fixture', type: 'boolean', value: false, description: 'Whether to enable the fixture extension.')
+option('extension_memory', type: 'boolean', value: false, description: 'Whether to enable the memory extension.')
+option('support_double', type: 'boolean', value: false, description: 'Whether to enable double precision floating point assertions.')