vendor libsecret

The libsecret-rs crate is unmaintained, so I'm vendoring it for
now. Bumping the glib version turned out to be enough.

The exact process I used was:
1. Cloning the repository
2. Making changes
3. `cargo build` to ensure it works
4. `cargo package --no-verify` (b/c it tries to build all crates
separately instead of the entire workspace as a whole)
5. `mkdir libsecret/sys -p`
6. `tar --strip-components 1 -C libsecret -xvf ../libsecret-rs/target/package/libsecret-0.6.0.crate`
7. `tar --strip-components 1 -C libsecret/sys -xvf ../libsecret-rs/target/package/libsecret-sys-0.6.0.crate`

Then `Cargo.toml` is modified to ensure the libsecret and its `-sys`
crate build out of my vendored sources.

In the future, if I gain maintainership of the `libsecret` crate, I
could just revert this commit to make it point back to the upstream.

1 files changed, 12 insertions, 0 deletions

diff --git a/libsecret/src/schema_attribute.rs b/libsecret/src/schema_attribute.rs
new file mode 100644
index 0000000..562381a
--- /dev/null
+++ b/libsecret/src/schema_attribute.rs
@@ -0,0 +1,12 @@
+use crate::{SchemaAttribute, SchemaAttributeType};
+use glib::translate::*;
+
+impl SchemaAttribute {
+    pub fn type_(&self) -> SchemaAttributeType {
+        unsafe { from_glib((*(self.as_ptr())).type_) }
+    }
+
+    pub fn name(&self) -> glib::GString {
+        unsafe { from_glib_none((*(self.as_ptr())).name) }
+    }
+}