switch to checkout@v2 with submodules and fetch-depth 0

In order to get tags, including in submodules, we use our own fetching
procedure on top of checkout@v2.

A problem occuring in about 1% of jobs was that some submodules inexplicably
did not have an "origin" remote configured.  "git submodule sync"
configures the "origin" remote in those cases.  No cause for the problem
was determined.

Besides keeping up to date on actions/checkout, @v2 is supposed to fix a bug
where "re-run" of a pull request would fail checking out the code.

.github/workflows/build.yml

@@ -16,6 +16,16 @@ jobs:
       env:
         GITHUB_CONTEXT: ${{ toJson(github) }}
       run: echo "$GITHUB_CONTEXT"
+    - uses: actions/checkout@v2
+      with:
+        submodules: true
+        fetch-depth: 0
+    - run: git fetch --recurse-submodules=no https://github.com/adafruit/circuitpython refs/tags/*:refs/tags/*
+    - run: git submodule sync
+    - run: git submodule foreach git remote -v
+    - run: git submodule foreach git fetch --recurse-submodules=no origin +refs/tags/*:refs/tags/*
+    - name: CircuitPython version
+      run: git describe --dirty --tags
     - name: Set up Python 3.8
       uses: actions/setup-python@v1
       with:
@@ -29,11 +39,6 @@ jobs:
       run: |
         gcc --version
         python3 --version
-    - uses: actions/checkout@v1
-      with:
-        submodules: true
-    - name: CircuitPython version
-      run: git describe --dirty --always --tags
     - name: Build mpy-cross
       run: make -C mpy-cross -j2
     - name: Build unix port
@@ -103,11 +108,16 @@ jobs:
         gcc --version
         python3 --version
         msgfmt --version
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
       with:
         submodules: true
+        fetch-depth: 0
+    - run: git fetch --recurse-submodules=no https://github.com/adafruit/circuitpython refs/tags/*:refs/tags/*
+    - run: git submodule sync
+    - run: git submodule foreach git remote -v
+    - run: git submodule foreach git fetch --recurse-submodules=no origin +refs/tags/*:refs/tags/*
     - name: CircuitPython version
-      run: git describe --dirty --always --tags
+      run: git describe --dirty --tags
     - name: Build mpy-cross
       run: make -C mpy-cross -j2
     - uses: actions/upload-artifact@v1.0.0
@@ -260,9 +270,14 @@ jobs:
         gcc --version
         arm-none-eabi-gcc --version
         python3 --version
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
       with:
         submodules: true
+        fetch-depth: 0
+    - run: git fetch --recurse-submodules=no https://github.com/adafruit/circuitpython refs/tags/*:refs/tags/*
+    - run: git submodule sync
+    - run: git submodule foreach git remote -v
+    - run: git submodule foreach git fetch --recurse-submodules=no origin +refs/tags/*:refs/tags/*
     - name: mpy-cross
       run: make -C mpy-cross -j2
     - name: build

.github/workflows/create_website_pr.yml

@@ -23,11 +23,14 @@ jobs:
       run: |
         gcc --version
         python3 --version
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
       with:
         submodules: true
+        fetch-depth: 0
+    - run: git fetch --recurse-submodules=no https://github.com/adafruit/circuitpython refs/tags/*:refs/tags/*
+    - run: git submodule foreach git fetch --recurse-submodules=no origin +refs/tags/*:refs/tags/*
     - name: CircuitPython version
-      run: git describe --dirty --always --tags
+      run: git describe --dirty --tags
     - name: Website
       run: python3 build_board_info.py
       working-directory: tools