Upgrade rust/crates/proc-macro-error to 1.0.4

Test: make
Change-Id: I3b48c3103904bb9e3e0b0a3e9cb7d91685cf88bd
diff --git a/Cargo.toml b/Cargo.toml
index fc90d7d..869585f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,7 +13,7 @@
 [package]
 edition = "2018"
 name = "proc-macro-error"
-version = "1.0.2"
+version = "1.0.4"
 authors = ["CreepySkeleton <[email protected]>"]
 build = "build.rs"
 description = "Almost drop-in replacement to panics in proc-macros"
@@ -25,7 +25,7 @@
 [package.metadata.docs.rs]
 targets = ["x86_64-unknown-linux-gnu"]
 [dependencies.proc-macro-error-attr]
-version = "=1.0.2"
+version = "=1.0.4"
 
 [dependencies.proc-macro2]
 version = "1"
@@ -35,8 +35,11 @@
 
 [dependencies.syn]
 version = "1"
-features = ["derive", "parsing", "proc-macro", "printing"]
+optional = true
 default-features = false
+[dev-dependencies.serde_derive]
+version = "=1.0.107"
+
 [dev-dependencies.toml]
 version = "=0.5.2"
 
@@ -45,5 +48,9 @@
 features = ["diff"]
 [build-dependencies.version_check]
 version = "0.9"
+
+[features]
+default = ["syn-error"]
+syn-error = ["syn"]
 [badges.maintenance]
 status = "passively-maintained"