Remove nightly version pin

Author: ijl

ci/azure-pipelines.yml

@@ -4,7 +4,7 @@ pr:
     - '*'
 
 variables:
-  toolchain: nightly-2020-06-09
+  toolchain: nightly
 
 jobs:
 

ci/drone.yml

@@ -14,7 +14,7 @@ steps:
     TWINE_PASSWORD:
       from_secret: twine_password
   commands:
-    - curl https://sh.rustup.rs -sSf | sh -s -- --default-toolchain nightly-2020-06-09 --profile minimal -y
+    - curl https://sh.rustup.rs -sSf | sh -s -- --default-toolchain nightly --profile minimal -y
     - python3.9 -m pip install --upgrade pip maturin
     - maturin build --no-sdist --release --strip --manylinux 2014 --interpreter python3.9
     - python3.9 -m pip install target/wheels/orjson*.whl
@@ -38,7 +38,7 @@ steps:
     TWINE_PASSWORD:
       from_secret: twine_password
   commands:
-    - curl https://sh.rustup.rs -sSf | sh -s -- --default-toolchain nightly-2020-06-09 --profile minimal -y
+    - curl https://sh.rustup.rs -sSf | sh -s -- --default-toolchain nightly --profile minimal -y
     - python3.8 -m pip install --upgrade pip maturin
     - maturin build --no-sdist --release --strip --manylinux 2014 --interpreter python3.8
     - python3.8 -m pip install target/wheels/orjson*.whl
@@ -62,7 +62,7 @@ steps:
     TWINE_PASSWORD:
       from_secret: twine_password
   commands:
-    - curl https://sh.rustup.rs -sSf | sh -s -- --default-toolchain nightly-2020-06-09 --profile minimal -y
+    - curl https://sh.rustup.rs -sSf | sh -s -- --default-toolchain nightly --profile minimal -y
     - python3.7 -m pip install --upgrade pip maturin
     - maturin build --no-sdist --release --strip --manylinux 2014 --interpreter python3.7
     - python3.7 -m pip install target/wheels/orjson*.whl
@@ -86,7 +86,7 @@ steps:
     TWINE_PASSWORD:
       from_secret: twine_password
   commands:
-    - curl https://sh.rustup.rs -sSf | sh -s -- --default-toolchain nightly-2020-06-09 --profile minimal -y
+    - curl https://sh.rustup.rs -sSf | sh -s -- --default-toolchain nightly --profile minimal -y
     - python3.6 -m pip install --upgrade pip maturin
     - maturin build --no-sdist --release --strip --manylinux 2014 --interpreter python3.6
     - python3.6 -m pip install target/wheels/orjson*.whl