chore(config): Fix unstable name collision with Mergeable::merge

[hashworks]

Summary

With rust 1.95.0 the build fails due to an unstable name collision in vector-config:

   Compiling vector-config v0.1.0 (/build/vector/src/vector/lib/vector-config)
error: a method with this name may be added to the standard library in the future
   --> lib/vector-config/src/schema/visitors/merge.rs:265:17
    |
265 |     destination.merge(source);
    |                 ^^^^^
    |
    = warning: once this associated item is added to the standard library, the ambiguity may cause an error or change in behavior!
    = note: for more information, see issue #48919 <[https://github.com/rust-lang/rust/issues/48919](https://github.com/rust-lang/rust/issues/48919)>
    = help: call with fully qualified syntax `Mergeable::merge(...)` to keep using the current method
note: the lint level is defined here
   --> lib/vector-config/src/lib.rs:104:9
    |
104 | #![deny(warnings)]
    |         ^^^^^^^^
    = note: `#[deny(unstable_name_collisions)]` implied by `#[deny(warnings)]`

error: could not compile `vector-config` (lib) due to 1 previous error
warning: build failed, waiting for other jobs to finish...

This fixes that.

How did you test this PR?

Included in the latest Arch Linux PKGBUILD to build with rust instead of rustup.

Change Type

• Bug fix
• New feature
• Dependencies
• Non-functional (chore, refactoring, docs)
• Performance

Is this a breaking change?

• Yes
• No

Does this PR include user facing changes?

• Yes. Please add a changelog fragment based on our guidelines.
• No. A maintainer will apply the no-changelog label to this PR.

References

https://gitlab.archlinux.org/archlinux/packaging/packages/vector/-/merge_requests/2