Version the protobuf_example crate the same as the other two crates.

The Cargo.toml sets both path and version for its dependencies: the mechanism is that path is used if possible (which it is for our test script), but is automatically stripped from the .toml file when uploadeded to Crates.io

PiperOrigin-RevId: 702721439

rust/release_crates/protobuf_example/BUILD

@@ -1,5 +1,6 @@
 load("@rules_pkg//pkg:mappings.bzl", "pkg_files", "strip_prefix")
 load("@rules_pkg//pkg:tar.bzl", "pkg_tar")
+load("//:protobuf_version.bzl", "PROTOBUF_RUST_VERSION")
 
 pkg_tar(
     name = "protobuf_example_crate",
@@ -16,8 +17,15 @@ pkg_files(
     strip_prefix = strip_prefix.from_root("rust/release_crates/protobuf_example"),
 )
 
+genrule(
+    name = "gen_cargo_toml",
+    srcs = ["Cargo-template.toml"],
+    outs = ["Cargo.toml"],
+    cmd = "cat $(SRCS) | sed -e 's/{{VERSION}}/{0}-beta/g' > $(OUTS)".format(PROTOBUF_RUST_VERSION),
+)
+
 filegroup(
     name = "srcs",
-    srcs = glob(["**/*"]),
+    srcs = [":gen_cargo_toml"] + glob(["**/*"]),
     visibility = ["//rust:__subpackages__"],
 )

rust/release_crates/protobuf_example/Cargo-template.toml

@@ -0,0 +1,10 @@
+[package]
+name = "protobuf-example"
+version = "{VERSION}"
+edition = "2021"
+
+[dependencies]
+protobuf = { version = "{VERSION}", path = "../protobuf" }
+
+[build-dependencies]
+protobuf-codegen = { version = "{VERSION}", path = "../protobuf_codegen" }