Attempt to fix *.yml confguration on Azure

Currently the `RUST_CONFIGURE_ARGS` variable apparently has a trailing
newline at the end of it due to the way it's configured in yaml. This
causes issues with MSVC's `install-clang.sh` step where the way the bash
syntax works out means that we drop the arg we're trying to add and it
doesn't actually get added!

The hopeful fix here is to tweak how we specify the yaml syntax to not
have a trailing newline, we'll see what CI says about this...

src/ci/azure-pipelines/auto.yml

@@ -318,7 +318,7 @@ jobs:
       # 32/64 bit MSVC and GNU deployment
       dist-x86_64-msvc:
         MSYS_BITS: 64
-        RUST_CONFIGURE_ARGS: >
+        RUST_CONFIGURE_ARGS: >-
           --build=x86_64-pc-windows-msvc
           --target=x86_64-pc-windows-msvc,aarch64-pc-windows-msvc
           --enable-full-tools
@@ -328,7 +328,7 @@ jobs:
         DEPLOY: 1
       dist-i686-msvc:
         MSYS_BITS: 32
-        RUST_CONFIGURE_ARGS: >
+        RUST_CONFIGURE_ARGS: >-
           --build=i686-pc-windows-msvc
           --target=i586-pc-windows-msvc
           --enable-full-tools