update changelog with link, one source of truth for RUST_VERSION

Author: softprops

CHANGELOG.md

@@ -1,10 +1,10 @@
-#  0.2.0-rust-1.31.2 (unreleased)
+#  0.2.0-rust-1.32.0 (unreleased)
 
-* Upgrade to Rust `1.13.2`
+* Upgrade to Rust [`1.32.0`](https://blog.rust-lang.org/2019/01/17/Rust-1.32.0.html)
 
 # 0.2.0-rust-1.31.1
 
-* Upgrade to Rust `1.13.1`
+* Upgrade to Rust [`1.13.1`](https://blog.rust-lang.org/2018/12/20/Rust-1.31.1.html)
 
 # 0.2.0-rust-1.31.0
 

Dockerfile

@@ -1,7 +1,7 @@
-# https://github.com/ilianaw/rust-crowbar/issues/20
 # https://github.com/lambci/docker-lambda#documentation
 FROM lambci/lambda:build-provided
-RUN curl https://sh.rustup.rs -sSf | sh -s -- -y --default-toolchain 1.31.2
+ARG RUST_VERSION
+RUN curl https://sh.rustup.rs -sSf | sh -s -- -y --default-toolchain $RUST_VERSION
 ADD build.sh /usr/local/bin/
 VOLUME ["/code"]
 WORKDIR /code

Makefile

@@ -1,5 +1,5 @@
 VERSION ?= 0.2.0
-RUST_VERSION ?= 1.31.2
+RUST_VERSION ?= 1.32.0
 REPO ?= softprops/lambda-rust
 TAG ?= "$(REPO):$(VERSION)-rust-$(RUST_VERSION)"
 
@@ -8,5 +8,5 @@ publish: build
 	docker push $(REPO):latest
 
 build:
-	docker build -t $(TAG) .
+	docker build --build-arg RUST_VERSION=$(RUST_VERSION) -t $(TAG) .
 	docker tag $(TAG) $(REPO):latest