rename duplicate examples

When testing the at the workspace level, there are warnings about
duplicate examples which may become a hard error from rust.  This PR
renames the examples.

```
❯ cargo test --release
warning: output filename collision.
The example target `basic` in package `opentelemetry-stdout v0.3.0 (/REDACTED/opentelemetry-rust/opentelemetry-stdout)` has the same output filename as the example target `basic` in package
`opentelemetry-appender-tracing v0.3.0 (/HOME/opentelemetry-rust/opentelemetry-appender-tracing)`.
Colliding filename is: /REDACTED/opentelemetry-rust/target/release/examples/basic
The targets should have unique names.  Consider changing their names to be unique or compiling them separately.  This may become a hard error in the future; see <rust-lang/cargo#6313>.
warning: output filename collision.
The example target `basic` in package `opentelemetry-stdout v0.3.0 (/REDACTED/opentelemetry-rust/opentelemetry-stdout)` has the same output filename as the example target `basic` in package `opentelemetry-appender-tracing v0.3.0 (/REDACTED/opentelemetry-rust/opentelemetry-appender-tracing)`.
Colliding filename is: /REDACTED/opentelemetry-rust/target/release/examples/basic
The targets should have unique names.  Consider changing their names to be unique or compiling them separately.  This may become a hard error in the future; see <rust-lang/cargo#6313>.
```

Author: Brian Caswell