Update Github Actions CI set-env/add-path (#2265)

In accordance with [this
advisory](https://github.blog/changelog/2020-10-01-github-actions-deprecating-set-env-and-add-path-commands/)
it's recommended we moved to a different scheme of setting env vars and
updating PATH.

.github/actions/binary-compatible-builds/main.js

@@ -2,19 +2,24 @@
 
 const child_process = require('child_process');
 const stdio = { stdio: 'inherit' };
+const fs = require('fs');
+
+function set_env(name, val) {
+  fs.appendFileSync(process.env['GITHUB_ENV'], `${name}=${val}\n`)
+}
 
 // On OSX all we need to do is configure our deployment target as old as
 // possible. For now 10.9 is the limit.
 if (process.platform == 'darwin') {
-  console.log("::set-env name=MACOSX_DEPLOYMENT_TARGET::10.9");
-  console.log("::set-env name=python::python3");
+  set_env("MACOSX_DEPLOYMENT_TARGET", "10.9");
+  set_env("python", "python3");
   return;
 }
 
 // On Windows we build against the static CRT to reduce dll dependencies
 if (process.platform == 'win32') {
-  console.log("::set-env name=RUSTFLAGS::-Ctarget-feature=+crt-static");
-  console.log("::set-env name=python::python");
+  set_env("RUSTFLAGS", "-Ctarget-feature=+crt-static");
+  set_env("python", "python");
   return;
 }
 
@@ -51,7 +56,7 @@ child_process.execFileSync('docker', [
 ], stdio);
 
 // Use ourselves to run future commands
-console.log(`::set-env name=CENTOS::${__filename}`)
+set_env("CENTOS", __filename);
 
 // See https://edwards.sdsu.edu/research/c11-on-centos-6/ for where these
 const exec = s => {
@@ -66,4 +71,4 @@ exec('yum install -y git');
 // This is a hack and not the right way to do this, but it ends up doing the
 // right thing for now.
 exec('rm -f /opt/rh/devtoolset-8/root/usr/lib/gcc/x86_64-redhat-linux/8/libstdc++.so');
-console.log("::set-env name=python::python3");
+set_env("python", "python3");

.github/actions/define-llvm-env/main.js

@@ -1,13 +1,19 @@
 #!/usr/bin/env node
 
+const fs = require('fs');
+
+function set_env(name, val) {
+  fs.appendFileSync(process.env['GITHUB_ENV'], `${name}=${val}\n`)
+}
+
 // On OSX pointing to brew's LLVM location.
 if (process.platform == 'darwin') {
-  console.log("::set-env name=DWARFDUMP::/usr/local/opt/llvm/bin/llvm-dwarfdump");
-  console.log("::set-env name=LLDB::/usr/local/opt/llvm/bin/lldb");
+  set_env("DWARFDUMP", "/usr/local/opt/llvm/bin/llvm-dwarfdump");
+  set_env("LLDB", "/usr/local/opt/llvm/bin/lldb");
 }
 
 // On Linux pointing to specific version
 if (process.platform == 'linux') {
-  console.log("::set-env name=DWARFDUMP::/usr/bin/llvm-dwarfdump-9");
-  console.log("::set-env name=LLDB::/usr/bin/lldb-9");
+  set_env("DWARFDUMP", "/usr/bin/llvm-dwarfdump-9");
+  set_env("LLDB", "/usr/bin/lldb-9");
 }

.github/actions/install-rust/main.js

@@ -1,10 +1,15 @@
 const child_process = require('child_process');
 const toolchain = process.env.INPUT_TOOLCHAIN;
+const fs = require('fs');
+
+function set_env(name, val) {
+  fs.appendFileSync(process.env['GITHUB_ENV'], `${name}=${val}\n`)
+}
 
 if (process.platform === 'darwin') {
   child_process.execSync(`curl https://sh.rustup.rs | sh -s -- -y --default-toolchain=none --profile=minimal`);
   const bindir = `${process.env.HOME}/.cargo/bin`;
-  console.log(`::add-path::${bindir}`);
+  fs.appendFileSync(process.env['GITHUB_PATH'], `${bindir}\n`);
   process.env.PATH = `${process.env.PATH}:${bindir}`;
 }
 
@@ -15,13 +20,13 @@ child_process.execFileSync('rustup', ['default', toolchain]);
 // Deny warnings on CI to keep our code warning-free as it lands in-tree. Don't
 // do this on nightly though since there's a fair amount of warning churn there.
 if (!toolchain.startsWith('nightly')) {
-  console.log(`::set-env name=RUSTFLAGS::-D warnings`);
+  set_env("RUSTFLAGS", "-D warnings");
 }
 
 // Save disk space by avoiding incremental compilation, and also we don't use
 // any caching so incremental wouldn't help anyway.
-console.log(`::set-env name=CARGO_INCREMENTAL::0`);
+set_env("CARGO_INCREMENTAL", "0");
 
 // Turn down debuginfo from 2 to 1 to help save disk space
-console.log(`::set-env name=CARGO_PROFILE_DEV_DEBUG::1`);
-console.log(`::set-env name=CARGO_PROFILE_TEST_DEBUG::1`);
+set_env("CARGO_PROFILE_DEV_DEBUG", "1");
+set_env("CARGO_PROFILE_TEST_DEBUG", "1");