Add serde_json dependencies back

Author: aumetra

examples/logs-basic/Cargo.toml

@@ -12,3 +12,4 @@ opentelemetry-stdout = { path = "../../opentelemetry-stdout", features = ["logs"
 opentelemetry-appender-log = { path = "../../opentelemetry-appender-log", default-features = false}
 opentelemetry-semantic-conventions = { path = "../../opentelemetry-semantic-conventions" }
 log = { workspace = true }
+serde_json = { workspace = true }

examples/metrics-advanced/Cargo.toml

@@ -10,3 +10,4 @@ opentelemetry = { path = "../../opentelemetry", features = ["metrics"] }
 opentelemetry_sdk = { path = "../../opentelemetry-sdk", features = ["metrics", "rt-tokio"] }
 opentelemetry-stdout = { path = "../../opentelemetry-stdout", features = ["metrics"]}
 tokio = { workspace = true, features = ["full"] }
+serde_json = { workspace = true }

examples/metrics-basic/Cargo.toml

@@ -10,6 +10,7 @@ opentelemetry = { path = "../../opentelemetry", features = ["metrics", "otel_uns
 opentelemetry_sdk = { path = "../../opentelemetry-sdk", features = ["metrics", "rt-tokio"] }
 opentelemetry-stdout = { path = "../../opentelemetry-stdout", features = ["metrics"]}
 tokio = { workspace = true, features = ["full"] }
+serde_json = { workspace = true }
 
 [features]
 default = ["otel_unstable"]