Add option to install Espressif RISC-V toolchain

Author: jessebraham

action.yaml

@@ -31,6 +31,9 @@ inputs:
   name:
     description: Xtensa Rust toolchain name
     default: esp
+  esp-riscv-gcc:
+    description: Install Espressif RISC-V toolchain built with croostool-ng
+    default: "false"
 
 runs:
   using: composite