Sync with 2.26.3

* maint-2.26:
  Git 2.26.3
  Git 2.25.5
  Git 2.24.4
  Git 2.23.4
  Git 2.22.5
  Git 2.21.4
  Git 2.20.5
  Git 2.19.6
  Git 2.18.5
  Git 2.17.6
  unpack_trees(): start with a fresh lstat cache
  run-command: invalidate lstat cache after a command finished
  checkout: fix bug that makes checkout follow symlinks in leading path

Documentation/RelNotes/2.17.6.txt

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+Git v2.17.6 Release Notes
+=========================
+
+This release addresses the security issues CVE-2021-21300.
+
+Fixes since v2.17.5
+-------------------
+
+ * CVE-2021-21300:
+   On case-insensitive file systems with support for symbolic links,
+   if Git is configured globally to apply delay-capable clean/smudge
+   filters (such as Git LFS), Git could be fooled into running
+   remote code during a clone.
+
+Credit for finding and fixing this vulnerability goes to Matheus
+Tavares, helped by Johannes Schindelin.

Documentation/RelNotes/2.18.5.txt

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+Git v2.18.5 Release Notes
+=========================
+
+This release merges up the fixes that appear in v2.17.6 to address
+the security issue CVE-2021-21300; see the release notes for that
+version for details.

Documentation/RelNotes/2.19.6.txt

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+Git v2.19.6 Release Notes
+=========================
+
+This release merges up the fixes that appear in v2.17.6 and
+v2.18.5 to address the security issue CVE-2021-21300; see the
+release notes for these versions for details.

Documentation/RelNotes/2.20.5.txt

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+Git v2.20.5 Release Notes
+=========================
+
+This release merges up the fixes that appear in v2.17.6, v2.18.5
+and v2.19.6 to address the security issue CVE-2021-21300; see
+the release notes for these versions for details.

Documentation/RelNotes/2.21.4.txt

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+Git v2.21.4 Release Notes
+=========================
+
+This release merges up the fixes that appear in v2.17.6, v2.18.5,
+v2.19.6 and v2.20.5 to address the security issue CVE-2021-21300;
+see the release notes for these versions for details.

Documentation/RelNotes/2.22.5.txt

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+Git v2.22.5 Release Notes
+=========================
+
+This release merges up the fixes that appear in v2.17.6,
+v2.18.5, v2.19.6, v2.20.5 and v2.21.4 to address the security
+issue CVE-2021-21300; see the release notes for these versions
+for details.

Documentation/RelNotes/2.23.4.txt

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+Git v2.23.4 Release Notes
+=========================
+
+This release merges up the fixes that appear in v2.17.6, v2.18.5,
+v2.19.6, v2.20.5, v2.21.4 and v2.22.5 to address the security
+issue CVE-2021-21300; see the release notes for these versions
+for details.

Documentation/RelNotes/2.24.4.txt

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+Git v2.24.4 Release Notes
+=========================
+
+This release merges up the fixes that appear in v2.17.6, v2.18.5,
+v2.19.6, v2.20.5, v2.21.4, v2.22.5 and v2.23.4 to address the
+security issue CVE-2021-21300; see the release notes for these
+versions for details.

Documentation/RelNotes/2.25.5.txt

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+Git v2.25.5 Release Notes
+=========================
+
+This release merges up the fixes that appear in v2.17.6, v2.18.5,
+v2.19.6, v2.20.5, v2.21.4, v2.22.5, v2.23.4 and v2.24.4 to address
+the security issue CVE-2021-21300; see the release notes for
+these versions for details.

Documentation/RelNotes/2.26.3.txt

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+Git v2.26.3 Release Notes
+=========================
+
+This release merges up the fixes that appear in v2.17.6, v2.18.5,
+v2.19.6, v2.20.5, v2.21.4, v2.22.5, v2.23.4, v2.24.4 and v2.25.5
+to address the security issue CVE-2021-21300; see the release
+notes for these versions for details.