GHA: silence fresh zizmor 1.21.0 warnings

- MSYS2/Cygwin bash shells are now tagged "misfeature".
  It is not something we can fix. We need these shells, and using
  documented/necessary settings to use these environments should be
  allowed without workarounds.

- untagged actions within curl's own organization are now also flagged
  as "action is not pinned to a hash (required by blanket policy)". This
  seems overkill. Making internal releases would not be helpful or
  practical. Also considering that the referred internal action uses an
  unpinned external action anyway (google/oss-fuzz/infra/cifuzz), with
  near-zero chance to fix.

Ref: https://github.com/zizmorcore/zizmor/pull/1517#issuecomment-3759740853

Closes #20339

.github/workflows/fuzz.yml

@@ -40,4 +40,4 @@ permissions: {}
 
 jobs:
   Fuzzing:
-    uses: curl/curl-fuzzer/.github/workflows/ci.yml@master
+    uses: curl/curl-fuzzer/.github/workflows/ci.yml@master  # zizmor: ignore[unpinned-uses]

.github/workflows/windows.yml

@@ -42,7 +42,7 @@ jobs:
     timeout-minutes: 10
     defaults:
       run:
-        shell: D:\cygwin\bin\bash.exe '{0}'
+        shell: D:\cygwin\bin\bash.exe '{0}'  # zizmor: ignore[misfeature]
     env:
       MAKEFLAGS: -j 5
       SHELLOPTS: 'igncr'
@@ -184,7 +184,7 @@ jobs:
     timeout-minutes: ${{ contains(matrix.tflags, '-t') && 14 || 10 }}
     defaults:
       run:
-        shell: msys2 {0}
+        shell: msys2 {0}  # zizmor: ignore[misfeature]
     env:
       MAKEFLAGS: -j 5
       MATRIX_BUILD: '${{ matrix.build }}'
@@ -412,7 +412,7 @@ jobs:
     timeout-minutes: 10
     defaults:
       run:
-        shell: msys2 {0}
+        shell: msys2 {0}  # zizmor: ignore[misfeature]
     env:
       CURL_TEST_MIN: 1550
       MAKEFLAGS: -j 5
@@ -696,7 +696,7 @@ jobs:
     timeout-minutes: ${{ matrix.arch == 'arm64' && 12 || 10 }}
     defaults:
       run:
-        shell: msys2 {0}
+        shell: msys2 {0}  # zizmor: ignore[misfeature]
     env:
       MATRIX_ARCH: '${{ matrix.arch }}'
       MATRIX_IMAGE: '${{ matrix.image }}'